1
|
Yu Z, Bai H, Li B, Li L, Pan H. Two-Dimensional Asymmetric Multiferroics: Unique Way toward Strong Magnetoelectric Coupling and Multistate Memory. J Phys Chem Lett 2024; 15:1795-1801. [PMID: 38329293 PMCID: PMC10895667 DOI: 10.1021/acs.jpclett.3c03527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Two-dimensional (2D) materials have provided a fascinating platform for exploring novel multiferroics and emergent magnetoelectric coupling mechanisms. Here, a novel 2D asymmetric multiferroic based on Janus 2D multiferroic MXene-analogous oxynitrides (InTlNO2) is presented by using first-principles calculations. We find three inequivalent phases for InTlNO2, including two metallic phases (p1 and p2) and one semiconducting phase (p3) with a band gap of 0.88 eV. All phases are room-temperature multiferroics with different Curie temperatures, leading to tunability by phase transitions. We show that there is a 90° rotation of the magnetic anisotropy easy axis between p1 and p2, where p1 favors the in-plane and p2 the out-of-plane easy axis. Therefore, the magnetic anisotropy can be tuned by reversing the out-of-plane polarization. Our strategy provides a unique way toward strong magnetoelectric coupling and multistate memory.
Collapse
Affiliation(s)
- Zhichao Yu
- Institute of Applied Physics and Materials Engineering, University of Macau, Macao SAR 999708, P. R. China
| | - Haoyun Bai
- Institute of Applied Physics and Materials Engineering, University of Macau, Macao SAR 999708, P. R. China
| | - Bowen Li
- 2027 Laboratory, Tianfu Xinglong Lake Laboratory, Chengdu, Sichuan 610000, P. R. China
| | - Lun Li
- Institute of Applied Physics and Materials Engineering, University of Macau, Macao SAR 999708, P. R. China
| | - Hui Pan
- Institute of Applied Physics and Materials Engineering, University of Macau, Macao SAR 999708, P. R. China
- Department of Physics and Chemistry, Faculty of Science and Technology, University of Macau, Macao SAR 999078, P. R. China
| |
Collapse
|
2
|
Wang F, Yue S, Han X, Zhang T, Han A, Wang L, Liu J. ZnS/C Dual-Quantum-Dots Heterostructural Nanofibers for High-Performance Photocatalytic H 2O 2 Production. ACS Appl Mater Interfaces 2024; 16:2606-2613. [PMID: 38175744 DOI: 10.1021/acsami.3c14183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2024]
Abstract
Constructing heterostructures of dual quantum-dots (QDs) is a promising way to achieve high performance in photocatalysis, but it still faces substantial synthetic challenges. Herein, we developed an in situ transformation strategy to coassemble ZnS QDs and C QDs into dual-quantum-dot heterostructural nanofibers (ZnS/C-DQDH). Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy results revealed the formation of strong Zn-O-C bonds at the interface between ZnS QDs and C QDs, improving the separation efficiency of photogenerated charge carriers. The ZnS/C-DQDH demonstrated remarkable photocatalytic activity in H2O2 production, with generation rates of 2896.4 μmol gcat-1 h-1 without sacrificial agents and 9879.3 μmol gcat-1 h-1 with ethanol as the sacrificial agent, significantly higher than the QD counterparts and surpassed state-of-the-art photocatalysts. Moreover, due to the nanofibrous feature, ZnS/C-DQDH demonstrated excellent stability and facile recyclability. This work provides a facile and large scalable method to gain dual-quantum-dot heterostructures and a promising alternative for photocatalytic H2O2 production.
Collapse
Affiliation(s)
- Fanping Wang
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China
| | - Shuang Yue
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China
| | - Xu Han
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China
| | - Tianyu Zhang
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China
| | - Aijuan Han
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China
| | - Lianying Wang
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China
| | - Junfeng Liu
- State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China
| |
Collapse
|
3
|
Alburaih HA, Nazir S, Noor NA, Laref A, Saad H-E MM. Physical properties of vacancy-ordered double perovskites K 2TcZ 6 (Z = Cl, Br) for spintronics applications: DFT calculations. RSC Adv 2024; 14:1822-1832. [PMID: 38192306 PMCID: PMC10772539 DOI: 10.1039/d3ra07603b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 12/27/2023] [Indexed: 01/10/2024] Open
Abstract
Vacancy-ordered double perovskites (DPs) are emerging materials for spintronics due to their stable structures and non-toxic properties. In this study, we conducted a comprehensive investigation into the role of 4d electrons in Tc to understand their impact on the ferromagnetic properties of K2TcY6 (Y = Cl, Br). We have employed a modified Back and Johnson potential to assess electronic and magnetic characteristics and utilized the BoltzTraP code to investigate thermoelectric effects. Experimental lattice constants confirmed the presence of stable structures and formation energy estimates affirmed their thermodynamic stability. The Heisenberg model and density of electron states (DOS) at the Fermi level provides insights into Curie temperature and spin polarization. The presence of ferromagnetism is evident in the density of states, reflecting the transition of electron spins that support the exchange mechanism. The study delves into how electron functionality influences the control of ferromagnetism, considering exchange constants, exchange energies, hybridization process and the crystal field energies. Moreover, the exploitation of magnetic moments from Tc to K and Cl/Br sites takes precedence in driving ferromagnetism by exchanging electron spins rather than forming magnetic clusters. Additionally, to explore the optical characteristics of the compounds, we investigated their optical absorption, dielectric constants and refractive index within the energy range of 0-10 eV, ensuring absorption across both the visible and ultraviolet regions. Finally, we delve into the impact of the thermoelectric effect on both thermoelectric performance and spin functionality, taking into account factors such as the Seebeck coefficient, power factor, and electronic conductivity.
Collapse
Affiliation(s)
- Huda A Alburaih
- Physics Department, College of Science, Princess Nourah Bint Abdulrahman University 11671 Riyadh 12211 Saudi Arabia
| | - Sadia Nazir
- Department of Physics, University of Lahore Pakistan
| | - N A Noor
- Department of Physics, RIPHAH International University, Campus Lahore Pakistan
| | - A Laref
- Department of Physics and Astronomy, College of Science, King Saud University Riyadh 11451 King Saudi Arabia
| | - M Musa Saad H-E
- Department of Physics, College of Science and Arts in Al-Muthnib, Qassim University Al-Muthnib 51931 Saudi Arabia
| |
Collapse
|
4
|
Nguyen DK, Ha CV, Hong Gam LT, Guerrero-Sanchez J, Hoat DM. First-principles study of indium nitride monolayers doped with alkaline earth metals. RSC Adv 2023; 13:33634-33643. [PMID: 38020031 PMCID: PMC10652252 DOI: 10.1039/d3ra04169g] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 11/04/2023] [Indexed: 12/01/2023] Open
Abstract
Element doping has been widely employed to modify the ground state properties of two-dimensional (2D) materials. In this work, the effects of doping with alkaline earth metals (AEMs) on the structural, electronic, and magnetic properties of indium nitride (InN) monolayers are investigated using first-principles calculations based on density functional theory. In a graphene-like honeycomb structure, the InN monolayer possesses good dynamical and thermal stability, and exhibits an indirect gap semiconductor character with a band gap of 0.37 (1.48) eV as determined by using the PBE(HSE06) functional. A single In vacancy leads to the emergence of a magnetic semiconductor character, where magnetic properties with a large total magnetic moment of 3.00 μB are produced mainly by the N atoms closest to the defect site. The incorporation of AEMs impurities causes local structural distortion due to the difference in atomic size, where Mg and Ca doping processes are energetically most favorable. Half-metallicity is induced by the partial occupancy of the N-2p orbital, which is a consequence of having one valence electron less. In these cases, the total magnetic moment of 1.00 μB mainly originates from N atoms neighboring the dopants. Further increasing the doping level preserves the half-metallic character, where N atoms play a key role on the magnetism of the highly doped systems. Results presented herein suggest the In replacement by AEMs impurities is an effective approach to make prospective spintronic 2D materials from InN monolayers.
Collapse
Affiliation(s)
- Duy Khanh Nguyen
- Laboratory for Computational Physics, Institute for Computational Science and Artificial Intelligence, Van Lang University Ho Chi Minh City Vietnam
- Faculty of Mechanical - Electrical and Computer Engineering, School of Technology, Van Lang University Ho Chi Minh City Vietnam
| | - Chu Viet Ha
- Faculty of Physics, TNU-University of Education Thai Nguyen 250000 Vietnam
| | - Le T Hong Gam
- Faculty of Physics, TNU-University of Education Thai Nguyen 250000 Vietnam
| | - J Guerrero-Sanchez
- Universidad Nacional Autónoma de México, Centro de Nanociencias y Nanotecnología Apartado Postal 14 Ensenada Baja California Código Postal 22800 Mexico
| | - D M Hoat
- Institute of Theoretical and Applied Research, Duy Tan University Ha Noi 100000 Vietnam
- Faculty of Natural Sciences, Duy Tan University Da Nang 550000 Vietnam
| |
Collapse
|
5
|
Awan SU, Akhtar MT, Hussain D, Shah SA, Rizwan S, Rafique M, Samad A, Arshad M. Defects mediated weak ferromagnetism in Zn 1-yC yO (0.00 ≤ y ≤ 0.10) nanorods semiconductors for spintronics applications. Sci Rep 2023; 13:17080. [PMID: 37816819 PMCID: PMC10564763 DOI: 10.1038/s41598-023-44102-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 10/03/2023] [Indexed: 10/12/2023] Open
Abstract
A series of carbon-doped ZnO [Zn1-yCyO (0.00 ≤ y ≤ 0.10)] nanorods were synthesized using a cost-effective low-temperature (85 °C) dip coating technique. X-ray diffractometer scans of the samples revealed the hexagonal structure of the C-doped ZnO samples, except for y = 0.10. XRD analysis confirmed a decrease in the unit cell volume after doping C into the ZnO matrix, likely due to the incorporation of carbon at oxygen sites (CO defects) resulting from ionic size differences. The morphological analysis confirmed the presence of hexagonal-shaped nanorods. X-ray photoelectron spectroscopy identified C-Zn-C bonding, i.e., CO defects, Zn-O-C bond formation, O-C-O bonding, oxygen vacancies, and sp2-bonded carbon in the C-doped ZnO structure with different compositions. We analyzed the deconvoluted PL visible broadband emission through fitted Gaussian peaks to estimate various defects for electron transition within the bandgap. Raman spectroscopy confirmed the vibrational modes of each constituent. We observed a stronger room-temperature ferromagnetic nature in the y = 0.02 composition with a magnetization of 0.0018 emu/cc, corresponding to the highest CO defects concentration and the lowest measured bandgap (3.00 eV) compared to other samples. Partial density of states analysis demonstrated that magnetism from carbon is dominant due to its p-orbitals. We anticipate that if carbon substitutes oxygen sites in the ZnO structure, the C-2p orbitals become localized and create two holes at each site, leading to enhanced p-p type interactions and strong spin interactions between carbon atoms and carriers. This phenomenon can stabilize the long-range order of room-temperature ferromagnetism properties for spintronic applications.
Collapse
Affiliation(s)
- Saif Ullah Awan
- Department of Electrical Engineering, NUST College of Electrical and Mechanical Engineering (CEME), National University of Sciences and Technology (NUST), Islamabad, 44000, Pakistan.
| | - M Tanveer Akhtar
- Department of Physics, COMSATS Institute of Information Technology, Islamabad, 44000, Pakistan
| | - Danish Hussain
- Department of Mechatronics Engineering, NUST College of Electrical and Mechanical Engineering, National University of Sciences and Technology (NUST), Islamabad, 44000, Pakistan
| | - Saqlain A Shah
- Department of Physics, Forman Christian College (University), Lahore, Pakistan
| | - Syed Rizwan
- Physics Characterization and Simulations Lab, School of Natural Sciences (SNS), National University of Sciences and Technology (NUST), Islamabad, 44000, Pakistan
| | - Mohsin Rafique
- Beijing Academy of Quantum Information Sciences, Beijing, China
| | - Abdus Samad
- Department of Physics, University of Ulsan, Ulsan, 44610, Republic of Korea
| | - M Arshad
- Nanosciences 7 Technology Department, National Centre for Physics, Islamabad, Pakistan
| |
Collapse
|
6
|
Meng R, Houssa M. Ferromagnetism in two-dimensional metal dibromides induced by hole-doping. Sci Rep 2023; 13:11521. [PMID: 37460596 DOI: 10.1038/s41598-023-37777-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 06/27/2023] [Indexed: 07/20/2023] Open
Abstract
Using spin-polarized first-principles calculations based on density functional theory, we study the stability, electronic properties and magnetic behavior induced by hole-doping of two-dimensional (2D) PbBr2 and HgBr2. Although inherently nonmagnetic, these materials can exhibit stable ferromagnetic order when hole-doped at densities above a few 1013 cm-2. We also examined the impact of intrinsic and extrinsic defects on inducing hole-doping and subsequent ferromagnetism. Our findings suggest that p-type doping can be achieved by Pb and Hg vacancies and Br antisites, but the latter behaves as deep acceptors. Among the possible dopants we considered, Li substituting Pb or Hg, and S replacing Br in 2D HgBr2, can produce shallow acceptor states near the valence band edges and potentially result in a stable ferromagnetic order in these 2D dibromides.
Collapse
Affiliation(s)
- Ruishen Meng
- Department of Physics and Astronomy, KU Leuven, Leuven, 3001, Belgium.
| | - Michel Houssa
- Department of Physics and Astronomy, KU Leuven, Leuven, 3001, Belgium.
- IMEC, Leuven, 3001, Belgium.
| |
Collapse
|
7
|
Abd-Elkader OH, Deraz NM, Aleya L. Rapid Bio-Assisted Synthesis and Magnetic Behavior of Zinc Oxide/Carbon Nanoparticles. Crystals 2023; 13:1081. [DOI: 10.3390/cryst13071081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
The biomimetic synthesis of a ZnO/C nanocomposite has been achieved using the egg white-assisted self-combustion method. The characterization of this composite has been carried out using different techniques, such as XRD, FTIR, Raman, SEM/EDS and TEM. A comparative study was conducted between ZnO in the form of this composite and pristine ZnO, which was prepared via the same procedures but without the egg white. The resulting ZnO had a hexagonal structure, similar to wurtzite, with a P63mc space group. When this egg white method was used to produce a ZnO-based material, a ZnO/C nanocomposite was developed, and the ZnO’s crystallite size was significantly decreased. The structural properties—including the unit cell volume, strain, atom displacement and dislocation density—of this ZnO crystal are increased as a result of the presence of a C atom. On the other hand, the length of the Zn–O bond is reduced by the presence of the C atom. Results derived from a combination of Raman, FTIR, and EDS demonstrate that the carbonaceous layers and ZnO nanoparticles were integrated with a close interfacial contact. The preparation method used here brought about obvious changes in the morphological and magnetic behaviors of the as-prepared materials. Using a small amount of egg white resulted in the transformation of the particle’s shape from a hexagonal cone-type structure to an ellipsoidal structure. Based on an analysis of diffuse reflectance, the ZnO and ZnO/C band gap values were revealed using UV–VIS spectra. ZnO and ZnO/C exhibit band gap energies of 3.09 and 2.60 eV, respectively. A phase transition from weakly ferromagnetic to completely diamagnetic magnetic was discovered.
Collapse
Affiliation(s)
- Omar H. Abd-Elkader
- Physics and Astronomy Department, Science College, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Nasrallah M. Deraz
- Physical Chemistry Department, National Research Centre, Giza P.O. Box 12622, Egypt
| | - Lotfi Aleya
- Chrono-Environnement Laboratory, UMR CNRS 6249, Bourgogne, Franche-Comté University, CEDEX, F-25030 Besançon, France
| |
Collapse
|
8
|
Shilkar OA, Adhikari R, Sappati S, Godi S, Desai AM. A first-principles study of electronic and magnetic properties of 4d transition metals doped in Wurtzite GaN for spintronics applications. J Mol Model 2023; 29:200. [PMID: 37269432 DOI: 10.1007/s00894-023-05529-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Accepted: 03/23/2023] [Indexed: 06/05/2023]
Abstract
We studied the electronic and magnetic properties of wurtzite GaN (w-GaN) doped with different concentrations of the 4d transition metal ions Nb, Mo, and Ru. We incorporated spin-polarized plane-wave density functional theory within an ultrasoft pseudopotential formalism. The 4d transition metals were doped at different geometrical sites to determine the geometry with the lowest total energy and the one that induced the largest magnetization. A spin-spin interaction study was performed to determine whether the doped compound was ferromagnetic or antiferromagnetic. The origin of magnetization in the transition metal-doped w-GaN compounds is due to the p-d hybridization of the nitrogen and 4d transition metals. From the bulk modulus results, we inferred that the structural integrity is preserved under compressive loads after doping w-GaN with these 4d transition metal ions. Our results indicate that these compounds can be used in spintronic applications.
Collapse
Affiliation(s)
- Omkar A Shilkar
- Department of Physics, Parvatibai Chowgule College of Arts and Science, Margao, 403602, Goa, India
- School of Physical and Applied Sciences, Goa University, Taleigão, 403206, Goa, India
| | - Rajendra Adhikari
- Department of Physics, Kathmandu University, Dhulikhel, 45200, Nepal
| | - Subrahmanyam Sappati
- Department of Pharmaceutical Technology and Biochemistry, Gdańsk University of Technology, Gdańsk, 80-233, Poland
- BioTechMed Center, Gdańsk University of Technology, Gdańsk, 80-233, Poland
| | - Shreya Godi
- Department of Physics, Parvatibai Chowgule College of Arts and Science, Margao, 403602, Goa, India
- School of Physical and Applied Sciences, Goa University, Taleigão, 403206, Goa, India
| | - Ashish M Desai
- Department of Physics, Parvatibai Chowgule College of Arts and Science, Margao, 403602, Goa, India.
| |
Collapse
|
9
|
Affiliation(s)
- Hemam Rachna Devi
- Materials Research Centre, Indian Institute of Science, Bangalore 560012, India
| | - Vanaraj Solanki
- Dr. K C Patel R & D Centre, Charotar University of Science & Technology (CHARUSAT), Changa 388 421, Anand, India
| | - Karuna Kar Nanda
- Materials Research Centre, Indian Institute of Science, Bangalore 560012, India
- Institute of Physics, P.O. Sainik School, Bhubaneswar 751005, India
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
| |
Collapse
|
10
|
Ren H, Xiang G. Morphology-Dependent Room-Temperature Ferromagnetism in Undoped ZnO Nanostructures. Nanomaterials (Basel) 2021; 11:3199. [PMID: 34947546 PMCID: PMC8708357 DOI: 10.3390/nano11123199] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 11/18/2021] [Accepted: 11/19/2021] [Indexed: 01/19/2023]
Abstract
Since Dietl et al. predicted that Co-doped ZnO may show room-temperature ferromagnetism (RTFM) in 2000, researchers have focused on the investigation of ferromagnetic ZnO doped with various transition metals. However, after decades of exploration, it has been found that undoped ZnO nanostructures can also show RTFM, which in general is dependent on ZnO morphologies. Here, we will give an overall review on undoped ZnO nanomaterials with RTFM. The advanced strategies to achieve multidimensional (quasi-0D, 1D, 2D, and 3D) ferromagnetic ZnO nanostructures and the mechanisms behind RTFM are systematically presented. We have successfully prepared ferromagnetic nanostructures, including thin films, horizontal arrays and vertical arrays. The existing challenges, including open questions about quantum-bound ZnO nanostructures, are then discussed.
Collapse
Affiliation(s)
- Hongtao Ren
- School of Materials Science and Engineering, Liaocheng University, Hunan Road No. 1, Liaocheng 252000, China
| | - Gang Xiang
- College of Physics, Sichuan University, Wangjiang Road No. 29, Chengdu 610064, China
| |
Collapse
|
11
|
Hong T, Jeong HJ, Lee HM, Choi SH, Lim JH, Park JS. Significance of Pairing In/Ga Precursor Structures on PEALD InGaO x Thin-Film Transistor. ACS Appl Mater Interfaces 2021; 13:28493-28502. [PMID: 34115464 DOI: 10.1021/acsami.1c06575] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Atomic layer deposition (ALD) is a promising deposition method to precisely control the thickness and metal composition of oxide semiconductors, making them attractive materials for use in thin-film transistors because of their high mobility and stability. However, multicomponent deposition using ALD is difficult to control without understanding the growth mechanisms of the precursors and reactants. Thus, the adsorption and surface reactivity of various precursors must be investigated. In this study, InGaO (IGO) semiconductors were deposited by plasma-enhanced atomic layer deposition (PEALD) using two sets of In and Ga precursors. The first set of precursors consisted of In(CH3)3[CH3OCH2CH2NHtBu] (TMION) and Ga(CH3)3[CH3OCH2CH2NHtBu]) (TMGON), denoted as TM-IGO; the other set of precursors was (CH3)2In(CH2)3N(CH3)2 (DADI) and (CH3)3Ga (TMGa), denoted as DT-IGO. We varied the number of InO subcycles between 3 and 19 to control the chemical composition of the ALD-processed films. The indium compositions of TM-IGO and DT-IGO thin films increased as the InO subcycles increased. However, the indium/gallium metal ratios of TM-IGO and DT-IGO were quite different, despite having the same InO subcycles. The steric hindrance of the precursors and different densities of the adsorption sites contributed to the different TM-IGO and DT-IGO metal ratios. The electrical properties of the precursors, such as Hall characteristics and device parameters of the thin-film transistors, were also different, even though the same deposition process was used. These differences might have resulted from the growth behavior, anion/cation ratios, and binding states of the IGO thin films.
Collapse
Affiliation(s)
- TaeHyun Hong
- Division of Materials Science and Engineering, Hanyang University, Seoul, Korea
| | - Hyun-Jun Jeong
- Division of Materials Science and Engineering, Hanyang University, Seoul, Korea
| | - Hyun-Mo Lee
- Division of Materials Science and Engineering, Hanyang University, Seoul, Korea
| | - Su-Hwan Choi
- Division of Nanoscale Semiconductor Engineering, Hanyang University, Seoul, Korea
| | | | - Jin-Seong Park
- Division of Materials Science and Engineering, Hanyang University, Seoul, Korea
- Division of Nanoscale Semiconductor Engineering, Hanyang University, Seoul, Korea
| |
Collapse
|
12
|
Li B, Geng J, Ai H, Kong Y, Bai H, Lo KH, Ng KW, Kawazoe Y, Pan H. Design of 2D materials - MSi 2C xN 4-x (M = Cr, Mo, and W; x = 1 and 2) - with tunable electronic and magnetic properties. Nanoscale 2021; 13:8038-8048. [PMID: 33900351 DOI: 10.1039/d1nr00461a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Two-dimensional (2D) materials have attracted increasing interest in the past decades due to their unique physical and chemical properties for diverse applications. In this work, we present a first-principles design on a novel 2D family, MSi2CxN4-x (M = Cr, Mo, and W; x = 1 and 2), based on density-functional theory (DFT). We find that all MSi2CxN4-x monolayers are stable by investigating their mechanic, dynamic, and thermodynamic properties. Interestingly, we see that the alignment of magnetic moments can be tuned to achieve non-magnetism (NM), ferromagnetism (FM), anti-ferromagnetism (AFM) or paramagnetism (PM) by arranging the positions of carbon atoms in the 2D systems. Accordingly, their electronic properties can be controlled to obtain semiconductor, half-metal, or metal. The FM states in half-metallic 2D systems are contributed to the hole-mediated double exchange, while the AFM states are induced by super-exchange. Our findings show that the physical properties of 2D systems can be tuned by compositional and structural engineering, especially the layer of C atoms, which may provide guidance on the design and fabrication of novel 2D materials with projected properties for multi-functional applications.
Collapse
Affiliation(s)
- Bowen Li
- Institute of Applied Physics and Materials Engineering, University of Macau, Macao SAR, 999078, P.R. China.
| | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Islam SE, Hang DR, Chen CH, Chou MMC, Liang CT, Sharma KH. Rational design of hetero-dimensional C-ZnO/MoS 2 nanocomposite anchored on 3D mesoporous carbon framework towards synergistically enhanced stability and efficient visible-light-driven photocatalytic activity. Chemosphere 2021; 266:129148. [PMID: 33310520 DOI: 10.1016/j.chemosphere.2020.129148] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 11/03/2020] [Accepted: 11/27/2020] [Indexed: 06/12/2023]
Abstract
For efficient solar energy harvesting, various engineering strategies to strengthen visible-light responsivity of ZnO photocatalyst is under intensive investigation. In this work, a new ternary C-ZnO/MoS2/mesoporous carbon nanocomposite was successfully prepared by a two-step solution-processed synthesis protocol. The ternary composite exhibits a well-interconnected 3D mesoporous microstructure assembled by carbon nanosheets, which is loaded with quasi 0D ZnO nanoparticles and 2D MoS2 nanosheets. The carbonaceous nanocomposites show enhanced visible-light-driven photocatalytic performance and high photo-corrosion resistance. The incorporation of carbon in the hybrid design has manifold benefits that drastically promotes the photoactivity and photostability. The significant enhancement in photodegradation activity of the hybrid catalysts can be ascribed to a few positive synergistic effects, such as increased surface area and active reaction sites, boosted surface charge utilization efficiency, and band-gap lowering. The high porosity of the distinct microstructure raises the dye adsorption within the material. Tailored interface/surface properties enable more effective mass transport and higher separation efficiency of photo-generated carriers. The modulated electronic structure leads to the narrowing of the ZnO optical bandgap. Meanwhile, coupling with carbon prevents ZnO from photo-corrosion. Our approach highlights the roles of carbon as structure directing and stabilizing agents as well as heteroatom in defect engineering for wide band-gap oxide materials. The rational material design of multivariate mixed-dimensional architecture also provides guiding insight for the advancement of heterogeneous photocatalyst materials with superior performance and durability. The presented engineering strategy would be a promising method for the preparation of nanomaterials supported on 3D carbon network with high porosity and visible-light-driven photocatalytic performance.
Collapse
Affiliation(s)
- Sk Emdadul Islam
- Department of Materials and Optoelectronic Science, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan; Department of Physics, National Taiwan University, Taipei, 10617, Taiwan
| | - Da-Ren Hang
- Department of Materials and Optoelectronic Science, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan; Center of Crystal Research, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan.
| | - Chun-Hu Chen
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan
| | - Mitch M C Chou
- Department of Materials and Optoelectronic Science, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan; Center of Crystal Research, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan
| | - Chi-Te Liang
- Department of Physics, National Taiwan University, Taipei, 10617, Taiwan.
| | - Krishna Hari Sharma
- Department of Materials and Optoelectronic Science, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan
| |
Collapse
|
14
|
Shivade RK, Kundu A, Chakraborty B. Room temperature d ferromagnetism in nitrogen doped WO3 for spintronic applications: A first-principles study. Chem Phys Lett 2021. [DOI: 10.1016/j.cplett.2020.138075] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
15
|
Zeng H, Wu M, Wang HQ, Zheng JC, Kang J. Tuning the Magnetism in Boron-Doped Strontium Titanate. Materials (Basel) 2020; 13:E5686. [PMID: 33322841 DOI: 10.3390/ma13245686] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 12/03/2020] [Accepted: 12/09/2020] [Indexed: 01/16/2023]
Abstract
The magnetic and electronic properties of boron-doped SrTiO3 have been studied by first-principles calculations. We found that the magnetic ground states of B-doped SrTiO3 strongly depended on the dopant-dopant separation distance. As the dopant–dopant distance varied, the magnetic ground states of B-doped SrTiO3 can have nonmagnetic, ferromagnetic or antiferromagnetic alignment. The structure with the smallest dopant-dopant separation exhibited the lowest total energy among all configurations considered and was characterized by dimer pairs due to strong attraction. Ferromagnetic coupling was observed to be stronger when the two adjacent B atoms aligned linearly along the B-Ti-B axis, which could be associated with their local bonding structures. Therefore, the symmetry of the local structure made an important contribution to the generation of a magnetic moment. Our study also demonstrated that the O-Ti-O unit was easier than the Ti-B-Ti unit to deform. The electronic properties of boron-doped SrTiO3 tended to show semiconducting or insulating features when the dopant–dopant distance was less than 5 Å, which changed to metallic properties when the dopant–dopant distance was beyond 5 Å. Our calculated results indicated that it is possible to manipulate the magnetism and band gap via different dopant–dopant separations.
Collapse
|
16
|
Kazmi J, Ooi PC, Goh BT, Lee MK, Razip Wee MFM, Shafura A Karim S, Ali Raza SR, Mohamed MA. Bi-doping improves the magnetic properties of zinc oxide nanowires. RSC Adv 2020; 10:23297-23311. [PMID: 35520345 PMCID: PMC9054718 DOI: 10.1039/d0ra03816d] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 06/03/2020] [Indexed: 12/18/2022] Open
Abstract
Room-temperature ferromagnetism in the large and direct bandgap diluted magnetic semiconductor zinc oxide (ZnO) is attributed to the intrinsic defects and p-orbital–p-orbital (p–p) coupling interaction. However, due to oxidation, the ferromagnetism induced by defects is unstable. In the present work, the solution process synthesis route was utilized to grow pristine and bismuth-doped, highly crystalline ZnO nanowire (ZnO NW)-based samples. The FE-SEM images showed that the grown ZnO NWs have a preferred orientation along the c-axis in the (001) direction due to the anisotropic crystal nature of ZnO. X-ray photoelectron spectroscopy (XPS) confirmed the presence of Bi, and at a higher doping content, the bismuth oxide phase appeared. The XRD patterns showed the wurtzite crystal structure, and the large intensity of the (002) peak suggests that most of the reflection was from the top hexagonal face of the NWs, and thus, the wires are predominantly aligned along the c-axis. The TEM analysis further confirmed the crystal growth direction along the (001) direction. The UV-Visible absorption and PL measurements also showed a decrease in the bandgap with an increase in doping concentration, which may be associated with the sp–d exchange interaction between the localized d-electrons and band electrons of the Bi ions. Bi-doping tended to increase the PL intensity in the visible region. The magnetic properties measured by SQUID at 4 and 300 K showed ferromagnetic behaviour for both the pristine and Bi-doped samples. However, the saturation magnetization for the Bi-doped samples was higher compared to that of the pristine ZnO samples until the threshold doping value. The obtained results demonstrated that Bi-doping can be used to tune both the optical and magnetic properties of ZnO NWs, hence paving the way for future spintronics and spin-polarized optoelectronics applications. Room-temperature ferromagnetism in the large and direct bandgap diluted magnetic semiconductor zinc oxide (ZnO) is attributed to the intrinsic defects and p-orbital–p-orbital (p–p) coupling interaction.![]()
Collapse
Affiliation(s)
- Jamal Kazmi
- Institute of Microengineering and Nanoelectronics, Universiti Kebangsaan Malaysia 43600 Bangi Malaysia +60 3 8925 0439 +60 3 8911 8157/8558
| | - Poh Choon Ooi
- Institute of Microengineering and Nanoelectronics, Universiti Kebangsaan Malaysia 43600 Bangi Malaysia +60 3 8925 0439 +60 3 8911 8157/8558
| | - Boon Tong Goh
- Low Dimensional Materials Research Centre (LDMRC), Department of Physics, Faculty of Science, University of Malaya 50603 Kuala Lumpur Malaysia
| | - Min Kai Lee
- Department of Physics, National Cheng-Kung University No. 1, University Rd. Tainan City 701 Taiwan
| | - M F Mohd Razip Wee
- Institute of Microengineering and Nanoelectronics, Universiti Kebangsaan Malaysia 43600 Bangi Malaysia +60 3 8925 0439 +60 3 8911 8157/8558
| | - Siti Shafura A Karim
- Institute of Microengineering and Nanoelectronics, Universiti Kebangsaan Malaysia 43600 Bangi Malaysia +60 3 8925 0439 +60 3 8911 8157/8558
| | - Syed Raza Ali Raza
- Department of Physics, University of Azad Jammu and Kashmir 13100 Muzaffarabad Pakistan
| | - Mohd Ambri Mohamed
- Institute of Microengineering and Nanoelectronics, Universiti Kebangsaan Malaysia 43600 Bangi Malaysia +60 3 8925 0439 +60 3 8911 8157/8558
| |
Collapse
|
17
|
Ameer S, Jindal K, Tomar M, Jha PK, Gupta V. The role of an unintentional carbon dopant in resolving the controversial conductivity aspects in BiFeO 3. Phys Chem Chem Phys 2020; 22:10010-10026. [PMID: 32337519 DOI: 10.1039/c9cp06614d] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Light elements like carbon may enter unintentionally into a material during material processing owing to their ubiquitous nature, and may significantly influence its observed electronic and magnetic properties. In the present work, the energetics and kinetics of carbon impurity related defects in BiFeO3 (BFO) are studied using first principles calculations in order to gain insight into the ongoing controversial aspects of conductivity of BFO. The results suggest that oxygen deficient conditions provide a favorable chemical environment for incorporation of carbon in BFO. Calculations based on the formation energy predict that carbon can spontaneously occupy interstitials, O, and Fe sites in BFO (where it is found to introduce impurity induced shallow acceptor type states at an energy of 0.05 eV above the valence band maximum). Carbon occupying cationic sites (CBi and CFe) tends to ionize their vacancies (VBi and VFe), resulting in the formation of a CO3 cluster, whereas it induces localized electron traps with energy levels composed of impurity states near the center of the band gap (0.9 eV above the valence band maximum) when occupying interstitial sites in BFO. An understanding of the migration of C impurity in BFO is developed, which suggests the favorable incorporation of carbon impurity via a vacancy mechanism. In order to confirm the theoretical results, experimental studies are carried out where BFO and carbon doped BFO (BCFO) thin films are grown by the pulsed laser deposition technique. Polycrystalline pure phase (R3c) thin films of BFO and BCFO are obtained. The presence of defect states in the deposited thin films is optically analyzed by the photoluminescence (PL) technique. In order to highlight the critical role of carbon in modifying the electrical conductivity of BFO, a BCFO/BFO/ITO based p-i-n heterojunction is prepared. The electrical characteristics depict remarkable rectifying characteristics, thus suggesting the p-type nature of carbon dopant in otherwise intrinsic BFO.
Collapse
Affiliation(s)
- Shaan Ameer
- Department of Physics and Astrophysics, University of Delhi, New Delhi-110007, India.
| | | | | | | | | |
Collapse
|
18
|
|
19
|
Liu W, Yin K, Yuan K, Zuo S, Yang S, Yao C, Chen M. In situ synthesis of Bi2MoO6@C@attapulgite photocatalyst for enhanced photocatalytic nitrogen fixation ability under simulated solar irradiation. Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2020.124488] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
20
|
Cui B, Zheng X, Wang J, Liu D, Xie S, Huang B. Realization of Lieb lattice in covalent-organic frameworks with tunable topology and magnetism. Nat Commun 2020; 11:66. [PMID: 31898693 PMCID: PMC6940388 DOI: 10.1038/s41467-019-13794-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 11/20/2019] [Indexed: 12/03/2022] Open
Abstract
Lieb lattice has been predicted to host various exotic electronic properties due to its unusual Dirac-flat band structure. However, the realization of a Lieb lattice in a real material is still unachievable. Based on tight-binding modeling, we find that the lattice distortion can significantly determine the electronic and topological properties of a Lieb lattice. Importantly, based on first-principles calculations, we predict that the two existing covalent organic frameworks (COFs), i.e., sp2C-COF and sp2N-COF, are actually the first two material realizations of organic-ligand-based Lieb lattice. Interestingly, the sp2C-COF can experience the phase transitions from a paramagnetic state to a ferromagnetic one and then to a Néel antiferromagnetic one, as the carrier doping concentration increases. Our findings not only confirm the first material realization of Lieb lattice in COFs, but also offer a possible way to achieve tunable topology and magnetism in organic lattices.
Collapse
Affiliation(s)
- Bin Cui
- School of Physics, National Demonstration Center for Experimental Physics Education, Shandong University, Jinan, 250100, China.
| | - Xingwen Zheng
- School of Physics, National Demonstration Center for Experimental Physics Education, Shandong University, Jinan, 250100, China
| | - Jianfeng Wang
- Beijing Computational Science Research Center, Beijing, 100193, China
| | - Desheng Liu
- School of Physics, National Demonstration Center for Experimental Physics Education, Shandong University, Jinan, 250100, China
| | - Shijie Xie
- School of Physics, National Demonstration Center for Experimental Physics Education, Shandong University, Jinan, 250100, China
| | - Bing Huang
- Beijing Computational Science Research Center, Beijing, 100193, China.
| |
Collapse
|
21
|
Chen W, Chen X, Wu Y, Liu G, Pan H. First-principles investigation of ScX2 (X = Cl, Br, or I) monolayers for flexible spintronic and electronic applications. Phys Chem Chem Phys 2020; 22:14781-14786. [DOI: 10.1039/d0cp02222e] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The promising two-dimensional ScX2 monolayer candidates for flexible spintronics applications.
Collapse
Affiliation(s)
- Wenzhou Chen
- School of Materials Science and Engineering
- Dongguan University of Technology
- Guangdong 523808
- China
| | - Xiaobing Chen
- School of Materials Science and Engineering
- Dongguan University of Technology
- Guangdong 523808
- China
| | - Yuzhen Wu
- School of Materials Science and Engineering
- Dongguan University of Technology
- Guangdong 523808
- China
| | - Guishan Liu
- School of Materials Science and Engineering
- Dongguan University of Technology
- Guangdong 523808
- China
| | - Hui Pan
- Joint Key Laboratory of the Ministry of Education
- Institute of Applied Physics and Materials Engineering
- University of Macau
- Macau
- China
| |
Collapse
|
22
|
Vo DD, Vu TV, Nguyen THT, Hieu NN, Phuc HV, Binh NTT, Idrees M, Amin B, Nguyen CV. Effects of electric field and strain engineering on the electronic properties, band alignment and enhanced optical properties of ZnO/Janus ZrSSe heterostructures. RSC Adv 2020; 10:9824-9832. [PMID: 35498594 PMCID: PMC9050402 DOI: 10.1039/d0ra00917b] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 02/27/2020] [Indexed: 12/21/2022] Open
Abstract
The formation of van der Waals heterostructures (vdWHs) have recently emerged as promising structures to make a variety of novel nanoelectronic and optoelectronic devices. Here, in this work, we investigate the structural, electronic and optical features of ZnO/ZrSSe vdWHs for different stacking patterns of ZnO/SeZrS and ZnO/SZrSe by employing first-principles calculations. Binding energy and ab initio molecular dynamics calculations are also employed to confirm the structural and thermal stability of the ZnO/ZrSSe vdWHs for both models. We find that in both stacking models, the ZnO and ZrSSe layers are bonded via weak vdW forces, leading to easy exfoliation of the layers. More interestingly, both the ZnO/SeZrS and ZnO/SZrSe vdWHs posses type-II band alignment, making them promising candidates for the use of photovoltaic devices because the photogenerated electrons–holes are separated at the interface. The ZnO/ZrSSe vdWHs for both models possess high performance absorption in the visible and near-infrared regions, revealing their use for acquiring efficient photocatalysts. Moreover, the band gap values and band alignments of the ZnO/ZrSSe for both models can be adjusted by an electric field as well as vertical strains. There is a transformation from semiconductor to metal under a negative electric field and tensile vertical strain. These findings demonstrate that ZnO/ZrSSe vdWHs are a promising option for optoelectronic and nanoelectronic applications. Here, in this work, we investigate the structural, electronic and optical features of ZnO/ZrSSe vdWHs for different stacking patterns of ZnO/SeZrS and ZnO/SZrSe by employing first-principles calculations.![]()
Collapse
Affiliation(s)
- Dat D. Vo
- Division of Computational Physics
- Institute for Computational Science
- Ton Duc Thang University
- Ho Chi Minh City
- Vietnam
| | - Tuan V. Vu
- Division of Computational Physics
- Institute for Computational Science
- Ton Duc Thang University
- Ho Chi Minh City
- Vietnam
| | - Thi H. Tham Nguyen
- Center of Excellence for Green Energy and Environmental Nanomaterials
- Nguyen Tat Thanh University
- Ho Chi Minh City
- Vietnam
| | - Nguyen N. Hieu
- Institute of Research and Development
- Duy Tan University
- Da Nang 550000
- Vietnam
| | - Huynh V. Phuc
- Division of Theoretical Physics
- Dong Thap University
- Cao Lanh 870000
- Vietnam
| | - Nguyen T. T. Binh
- Institute of Research and Development
- Duy Tan University
- Da Nang 550000
- Vietnam
| | - M. Idrees
- Department of Physics
- Hazara University
- Mansehra 21300
- Pakistan
| | - B. Amin
- Department of Physics
- Abbottabad University of Science and Technology
- Abbottabad 22010
- Pakistan
| | - Chuong V. Nguyen
- Department of Materials Science and Engineering
- Le Quy Don Technical University
- Ha Noi 100000
- Vietnam
| |
Collapse
|
23
|
Geng J, Chan IN, Ai H, Lo KH, Kawazoe Y, Ng KW, Pan H. Magnetic and electronic properties of 2D TiX3 (X = F, Cl, Br and I). Phys Chem Chem Phys 2020; 22:17632-17638. [DOI: 10.1039/d0cp02072a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A two-step transition in the magnetic state occurs in bilayer TiI3 under applied strain.
Collapse
Affiliation(s)
- Jiazhong Geng
- Institute of Applied Physics and Materials Engineering
- University of Macau
- Macao
- P. R. China
| | - Iat Neng Chan
- Department of Physics and Chemistry, Faculty of Science and Technology, University of Macau
- P. R. China
| | - Haoqiang Ai
- Department of Electrochemical Engineering, Faculty of Science and Technology
- University of Macau
- P. R. China
| | - Kin Ho Lo
- Department of Electrochemical Engineering, Faculty of Science and Technology
- University of Macau
- P. R. China
| | - Yoshiyuki Kawazoe
- New Industry Creation Hatchery Center
- Tohoku University
- Sendai
- Japan
- Department of Physics and Nanotechnology, SRM Institute of Science and Technology
| | - Kar Wei Ng
- Institute of Applied Physics and Materials Engineering
- University of Macau
- Macao
- P. R. China
| | - Hui Pan
- Institute of Applied Physics and Materials Engineering
- University of Macau
- Macao
- P. R. China
- Department of Physics and Chemistry, Faculty of Science and Technology, University of Macau
| |
Collapse
|
24
|
Mahmood Q, Hassan M, Yaseen M, Laref A. Half-metallic ferromagnetism and optical behavior in alkaline-earth metals based Beryllium perovskites: DFT calculations. Chem Phys Lett 2019. [DOI: 10.1016/j.cplett.2019.05.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
25
|
Bah A, Lim KY, Wei F, Khursheed A, Sow CH. Fluorescence Invigoration in Carbon-Incorporated Zinc Oxide Nanowires from Passage of Field Emission Electrons. Sci Rep 2019; 9:9671. [PMID: 31273272 PMCID: PMC6609609 DOI: 10.1038/s41598-019-46177-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 06/20/2019] [Indexed: 11/09/2022] Open
Abstract
We demonstrate that carbon incorporated Zinc Oxide (C-ZnO) nanowires (NWs) exhibit remarkable improvement in the extent and quality of fluorescence emission after they are utilized as an electron source in a field emission experiment. After the passage of field emission electrons, the intensity of the fluorescence emitted from these NWs in the visible light range exhibits a 2.5 to 8 fold enhancement. The intrinsic exciton peak of the ZnO also becomes heightened, along with the crystalline quality of the NWs showing marked improvement. This invigoration of fluorescence across the entire fluorescence spectrum is attributed to concurrent removal of oxygen and carbon atoms in C-ZnO NWs due to electro-migration of atoms and joule heating during the field emission process. Applications based on ZnO NWs emission from excitonic emissions or visible wavelength emissions or both can benefit from this straightforward method of defect engineering.
Collapse
Affiliation(s)
- Andrew Bah
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117542, Singapore
| | - Kim Yong Lim
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117542, Singapore
| | - Fuhua Wei
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117542, Singapore
| | - Anjam Khursheed
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore, 117583, Singapore
| | - Chorng Haur Sow
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117542, Singapore.
| |
Collapse
|
26
|
Beltrán JJ, Barrero CA, Punnoose A. Relationship between ferromagnetism and formation of complex carbon bonds in carbon doped ZnO powders. Phys Chem Chem Phys 2019; 21:8808-8819. [DOI: 10.1039/c9cp01277j] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Carbon doped ZnO powders showed RTFM. Hybridization of Zn 4s–C 2p mediated by oxygens is the likely source of the FM behavior. C–Zn–C bonds encourage the AFM signal.
Collapse
Affiliation(s)
- Jailes J. Beltrán
- Facultad de Ciencias Básicas
- Departamento de Química
- Universidad de Córdoba
- Montería
- Colombia
| | - Cesar A. Barrero
- Grupo de Estado Sólido
- Facultad de Ciencias Exactas y Naturales
- Universidad de Antioquia – UdeA
- Medellín
- Colombia
| | | |
Collapse
|
27
|
|
28
|
Pimachev A, Rimal G, Nielsen RD, Tang J, Dahnovsky Y. Room temperature d 0 ferromagnetism in PbS films: nonuniform distribution of Pb vacancies. Phys Chem Chem Phys 2018; 20:29804-29810. [PMID: 30465566 DOI: 10.1039/c8cp04882g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Because of the importance of ferromagnetism at room temperature, we search for new materials that can exhibit a non-vanishing magnetic moment at room temperature and at the same time can be used in spintronics. The experimental results indicate that d0 ferromagnetism without any magnetic impurities takes place in PbS films made of close-packed lead sulfide nanoparticles of 30 nm. To explain the existence of the d0 ferromagnetism, we propose a model where various PbS bulk and surface configurations of Pb-vacancies are analyzed. The bulk configurations have a zero magnetic moment while the two surface configurations with Pb vacancies with the same non-vanishing magnetic moments and lowest ground state energies contribute to the total magnetization. Based on the experimental value of the saturation magnetization, 0.2 emu g-1, we have found that the calculated Pb vacancy concentration should be about 3.5%, which is close to typical experimental values. Besides being very important for applications, there is one feature of PbS d0 ferromagnetism that makes this material special for fundamental research: PbS ferromagnetism can exhibit topologically driven spatial magnetic moment distributions (e.g., magnetic skyrmions) due to large spin-orbit coupling.
Collapse
Affiliation(s)
- Artem Pimachev
- Department of Physics & Astronomy/3905, 1000 E. University Avenue, University of Wyoming, Laramie, WY 82071, USA.
| | | | | | | | | |
Collapse
|
29
|
LingPing Xiao, Li X, Zeng L. High-Pressure Electronic Structure and Optical Properties of N-Doped ZnO. Russ J Phys Chem 2018. [DOI: 10.1134/s0036024418100382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
30
|
Albanese E, Ruiz Puigdollers A, Pacchioni G. Theory of Ferromagnetism in Reduced ZrO 2-x Nanoparticles. ACS Omega 2018; 3:5301-5307. [PMID: 31458739 PMCID: PMC6641900 DOI: 10.1021/acsomega.8b00667] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 05/04/2018] [Indexed: 06/10/2023]
Abstract
Bulk ZrO2 is both nonreducible and nonmagnetic. Recent experimental results show that dopant-free, oxygen-deficient ZrO2-x nanostructures exhibit a ferromagnetic behavior at room temperature (RT). Here, we provide a comprehensive theoretical foundation for the observed RT ferromagnetism of zirconia nanostructures. ZrO2 nanoparticles containing up to 700 atoms (3 nm) have been studied with the help of density functional theory. Oxygen vacancies in ZrO2 nanoparticles form more easily than in bulk zirconia and result in electrons trapped in 4d levels of low-coordinated Zr ions. Provided the number of these sites exceeds that of excess electrons, the resulting ground state is high spin and the ordering is ferromagnetic. The work provides a general basis to explain magnetism in intrinsically nonmagnetic oxides without the help of dopants.
Collapse
Affiliation(s)
- Elisa Albanese
- Dipartimento di Scienza dei
Materiali, Università di Milano-Bicocca, via R. Cozzi 55, 20125 Milano, Italy
| | - Antonio Ruiz Puigdollers
- Dipartimento di Scienza dei
Materiali, Università di Milano-Bicocca, via R. Cozzi 55, 20125 Milano, Italy
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei
Materiali, Università di Milano-Bicocca, via R. Cozzi 55, 20125 Milano, Italy
| |
Collapse
|
31
|
Wang YF, Shao YC, Hsieh SH, Chang YK, Yeh PH, Hsueh HC, Chiou JW, Wang HT, Ray SC, Tsai HM, Pao CW, Chen CH, Lin HJ, Lee JF, Wu CT, Wu JJ, Chang YM, Asokan K, Chae KH, Ohigashi T, Takagi Y, Yokoyama T, Kosugi N, Pong WF. Origin of magnetic properties in carbon implanted ZnO nanowires. Sci Rep 2018; 8:7758. [PMID: 29773822 DOI: 10.1038/s41598-018-25948-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 04/23/2018] [Indexed: 11/09/2022] Open
Abstract
Various synchrotron radiation-based spectroscopic and microscopic techniques are used to elucidate the room-temperature ferromagnetism of carbon-doped ZnO-nanowires (ZnO-C:NW) via a mild C+ ion implantation method. The photoluminescence and magnetic hysteresis loops reveal that the implantation of C reduces the number of intrinsic surface defects and increases the saturated magnetization of ZnO-NW. The interstitial implanted C ions constitute the majority of defects in ZnO-C:NW as confirmed by the X-ray absorption spectroscopic studies. The X-ray magnetic circular dichroism spectra of O and C K-edge respectively indicate there is a reduction in the number of unpaired/dangling O 2p bonds in the surface region of ZnO-C:NW and the C 2p-derived states of the implanted C ions strongly affect the net spin polarization in the surface and bulk regions of ZnO-C:NW. Furthermore, these findings corroborate well with the first-principles calculations of C-implanted ZnO in surface and bulk regions, which highlight the stability of implanted C for the suppression and enhancement of the ferromagnetism of the ZnO-C:NW in the surface region and bulk phase, respectively.
Collapse
|
32
|
Lu Q, Zhao Q, Yang T, Zhai C, Wang D, Zhang M. Preparation of Boron Nitride Nanoparticles with Oxygen Doping and a Study of Their Room-Temperature Ferromagnetism. ACS Appl Mater Interfaces 2018; 10:12947-12953. [PMID: 29629754 DOI: 10.1021/acsami.7b17932] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
In this work, oxygen-doped boron nitride nanoparticles with room-temperature ferromagnetism have been synthesized by a new, facile, and efficient method. There are no metal magnetic impurities in the nanoparticles analyzed by X-ray photoelectron spectroscopy. The boron nitride nanoparticles exhibit a parabolic shape with increase in the reaction time. The saturation magnetization value reaches a maximum of 0.2975 emu g-1 at 300 K when the reaction time is 12 h, indicating that the Curie temperature ( TC) is higher than 300 K. Combined with first-principles calculation, the coupling between B 2p orbital, N 2p orbital, and O 2p orbital in the conduction bands is the main origin of room-temperature ferromagnetism and also proves that the magnetic moment changes according the oxygen-doping content change. Compared with other room temperature ferromagnetic semiconductors, boron nitride nanoparticles have widely potential applications in spintronic devices because of high temperature oxidation resistance and excellent chemical stability.
Collapse
Affiliation(s)
- Qing Lu
- State Key Laboratory of Superhard Materials , Jilin University , Changchun 130012 , People's Republic of China
| | - Qi Zhao
- State Key Laboratory of Superhard Materials , Jilin University , Changchun 130012 , People's Republic of China
| | - Tianye Yang
- State Key Laboratory of Superhard Materials , Jilin University , Changchun 130012 , People's Republic of China
| | - Chengbo Zhai
- State Key Laboratory of Superhard Materials , Jilin University , Changchun 130012 , People's Republic of China
| | - Dongxue Wang
- State Key Laboratory of Superhard Materials , Jilin University , Changchun 130012 , People's Republic of China
| | - Mingzhe Zhang
- State Key Laboratory of Superhard Materials , Jilin University , Changchun 130012 , People's Republic of China
| |
Collapse
|
33
|
Majumder T, Dhar S, Chakraborty P, Mondal SP. Growth of Carbon-Functionalized, Carbon-Doped ZnO/C Core-Shell Nanorods for Photoelectrochemical Solar Energy Conversion. ChemistrySelect 2018. [DOI: 10.1002/slct.201702750] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Tanmoy Majumder
- Department of Physics; National Institute of Technology; Agartala India−79904
| | - Saurab Dhar
- Department of Physics; National Institute of Technology; Agartala India−79904
| | - Pinak Chakraborty
- Department of Physics; National Institute of Technology; Agartala India−79904
| | | |
Collapse
|
34
|
Shi X, Huang Z, Huttula M, Li T, Li S, Wang X, Luo Y, Zhang M, Cao W. Introducing Magnetism into 2D Nonmagnetic Inorganic Layered Crystals: A Brief Review from First-Principles Aspects. Crystals 2018; 8:24. [DOI: 10.3390/cryst8010024] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
|
35
|
Chen W, Kawazoe Y, Shi X, Pan H. Two-dimensional pentagonal CrX (X = S, Se or Te) monolayers: antiferromagnetic semiconductors for spintronics and photocatalysts. Phys Chem Chem Phys 2018; 20:18348-18354. [DOI: 10.1039/c8cp02470g] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This work proposes a new family of 2D pentagonal CrX (X = S, Se or Te) monolayers for their applications into electronics, spintronics and photocatalysis, based on the first-principles calculations.
Collapse
Affiliation(s)
- Wenzhou Chen
- Institute of Applied Physics and Materials Engineering
- University of Macau
- Macao SAR
- P. R. China
| | - Yoshiyuki Kawazoe
- New Industry Creation Hatchery Center
- Tohoku University
- Sendai
- Japan
- Department of Physics and Nanotechnology
| | - Xingqiang Shi
- Department of Physics
- Southern University of Science and Technology
- Shenzhen 518055
- China
| | - Hui Pan
- Institute of Applied Physics and Materials Engineering
- University of Macau
- Macao SAR
- P. R. China
| |
Collapse
|
36
|
Hariwal R, Malik HK, Negi A, Kandasami A. Controlling room temperature ferromagnetism and band gap in ZnO nanostructured thin films by varying angle of implantation. RSC Adv 2018; 8:6278-6287. [PMID: 35540397 PMCID: PMC9078269 DOI: 10.1039/c7ra10615g] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 01/30/2018] [Indexed: 01/29/2023] Open
Abstract
The defects in the host lattice play a major role in tuning the surface roughness, optical band gap and the room temperature ferromagnetism of ZnO thin films.
Collapse
Affiliation(s)
| | - Hitendra K. Malik
- Department of Physics
- Indian Institute of Technology Delhi
- New Delhi-110016
- India
| | - Ambika Negi
- Department of Physics
- Acharya Narendra Dev College
- University of Delhi
- New Delhi-110019
- India
| | | |
Collapse
|
37
|
Zhang H, Liu G, Cao Y, Chen J, Shen K, Kumar A, Xu M, Li Q, Xu Q. The magnetic and adsorption properties of ZnO 1-xS x nanoparticles. Phys Chem Chem Phys 2017; 19:26918-26925. [PMID: 28956045 DOI: 10.1039/c7cp03470a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Sulfur is easy to be incorporated into ZnO nanoparticles by the solution-combustion method. Herein, the magnetic and adsorption properties of a series of ZnO1-xSx (x = 0, 0.05, 0.1, 0.15, and 0.2) nanoparticles were systematically investigated. The X-ray diffraction patterns show that the as-prepared ZnO1-xSx nanoparticles have the hexagonal wurtzite structure of ZnO with a low sulfur content that gradually transforms into the zinc blende structure of ZnS when the x value is greater than 0.1. PL spectra show several bands due to different transitions, which have been explained by the recombination of free excitons or defect-induced transitions. The introduction of sulfur not only modifies the bandgap of ZnO, but also impacts the concentration of Zn vacancies. The as-prepared ZnO shows weak room-temperature ferromagnetism, and the incorporation of sulfur improves the ferromagnetism owing to the increased concentration of Zn vacancies, which may be stabilized by the doped sulfur ions. The adsorption capability of ZnO1-xSx nanoparticles has been significantly improved, and the process can be well described by the pseudo-first-order kinetic model and the Freundlich isotherm model. The mechanism has been confirmed to be due to the active sulfate groups existing in zinc oxysulfide nanoparticles.
Collapse
Affiliation(s)
- Huiyun Zhang
- School of Physics, Southeast University, Nanjing 211189, China.
| | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Pei Q, Song Y, Wang X, Zou J, Mi W. Superior Electronic Structure in Two-Dimensional MnPSe 3 /MoS 2 van der Waals Heterostructures. Sci Rep 2017; 7:9504. [PMID: 28842707 PMCID: PMC5573407 DOI: 10.1038/s41598-017-10145-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 08/02/2017] [Indexed: 11/09/2022] Open
Abstract
We explore the electronic structure of two-dimensional (2D) MnPSe3/MoS2 van der Waals (vdW) heterostructures based on density functional theory. A novel spin splitting at the valance band maximum of MnPSe3 appears in some specific stacking models due to Mn d orbital hybridization. The simultaneous spin and valley splitting can be achieved by interfacial coupling, which is attractive for manipulation of the valley and spin degrees of freedom. More importantly, due to the antiferromagnetic ordering of manganese, the opposite spin moments at K and K′ valleys can be observed by transforming configurations, which realizes the tunable spin splitting states. Our theoretical work opens up the opportunities of valley and spin related applications of MnPSe3/MoS2 vdW heterostructures and offers a practical avenue for exploring novel devices based on the spin and valley degrees of freedom.
Collapse
Affiliation(s)
- Qi Pei
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology, School of Science, Tianjin University, Tianjin, 300354, China
| | - Yan Song
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology, School of Science, Tianjin University, Tianjin, 300354, China
| | - Xiaocha Wang
- School of Electrical and Electronic Engineering, Tianjin University of Technology, Tianjin, 300384, China
| | - Jijun Zou
- Key Laboratory for Green Chemical Technology of the Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300354, China
| | - Wenbo Mi
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology, School of Science, Tianjin University, Tianjin, 300354, China.
| |
Collapse
|
39
|
|
40
|
Saravanan K, Jayalakshmi G, Chandra S, Panigrahi BK, Krishnan R, Sundaravel B, Annapoorani S, Shukla DK, Rajput P, Kanjilal D. The influence of carbon concentration on the electronic structure and magnetic properties of carbon implanted ZnO thin films. Phys Chem Chem Phys 2017; 19:13316-13323. [PMID: 28492651 DOI: 10.1039/c7cp01939d] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The influence of carbon concentration on the electronic and magnetic properties of C-implanted ZnO thin films has been studied using synchrotron radiation based X-ray absorption spectroscopic techniques and vibrating sample magnetometer measurements. 20 keV carbon ions were implanted in ZnO films with different fluences (2 × 1016, 4 × 1016 and 6 × 1016 ions per cm2). The pristine ZnO film shows diamagnetic behaviour while the C-implanted films exhibit room temperature ferromagnetism. Our first-principles calculations based on density functional theory show an appreciable magnetic moment only when the implanted C atom sits either in the O-site (2 μB) or in the interstitial position (1.88 μB), whereas the C atom in the Zn substitutional position does not possess any magnetic moment. X-ray absorption near edge structure analysis at the O K-edge reveals that the charge transfer from O-2p to the C-defect site causes the ferromagnetism in the C-implanted ZnO film at low fluence. However at high fluence, the implanted C replaces the lattice and produces more Zn vacancies, as evidenced by extended X-ray absorption fine structure studies at the Zn K-edge, which favors the ferromagnetism. The persistence of the implanted carbon and ferromagnetism of the C-implanted ZnO film has also been studied by isothermal annealing at 500 °C and discussed in detail.
Collapse
Affiliation(s)
- K Saravanan
- Material Science Group, Indira Gandhi Centre for Atomic Research, HBNI, Kalpakkam - 603102, India.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Feng YP, Shen L, Yang M, Wang A, Zeng M, Wu Q, Chintalapati S, Chang CR. Prospects of spintronics based on 2D materials. WIREs Comput Mol Sci 2017. [DOI: 10.1002/wcms.1313] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Yuan Ping Feng
- Department of Physics; National University of Singapore; Singapore
- Centre for Advanced Two-dimensional Materials; National University of Singapore; Singapore
| | - Lei Shen
- Department of Mechanical Engineering; National University of Singapore; Singapore
- Engineering Science Programme; National University of Singapore; Singapore
| | - Ming Yang
- Institute of Materials Science and Engineering; A*STAR; Singapore
| | - Aizhu Wang
- Department of Physics; National University of Singapore; Singapore
- Department of Electrical and Computer Engineering; National University of Singapore; Singapore
| | | | - Qingyun Wu
- Department of Materials Science and Engineering; National University of Singapore; Singapore
| | - Sandhya Chintalapati
- Centre for Advanced Two-dimensional Materials; National University of Singapore; Singapore
| | | |
Collapse
|
42
|
Ye H, Su Z, Tang F, Wang M, Chen G, Wang J, Xu S. Excitation Dependent Phosphorous Property and New Model of the Structured Green Luminescence in ZnO. Sci Rep 2017; 7:41460. [PMID: 28150699 PMCID: PMC5288693 DOI: 10.1038/srep41460] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 12/13/2016] [Indexed: 11/24/2022] Open
Abstract
The copper induced green luminescence (GL) with two sets of fine structures in ZnO crystal has been found for several decades (i.e., R. Dingle, Phys. Rev. Lett. 23, 579 (1969)), but the physical origin of the doublet still remains as an open question up to now. In this paper, we provide new insight into the mechanism of the structured GL band in terms of new experimental findings and theoretical calculations. It is found, for the first time, that the GL signal exhibits persistent afterglow for tens of minutes after the switch-off of below-band-gap excitation light but it cannot occur under above-band-gap excitation. Such a phosphorous property may be interpreted as de-trapping and feeding of electrons from a shallow trapping level via the conduction band to the Cu-related luminescence centers where the Cu3+ ion is proposed to work as the final state of the GL emission. From first-principles calculation, such a Cu3+ ion in wurtzite ZnO prefers a high spin 3d8 state with two non-degenerated half-filled orbitals due to the Jahn-Teller effect, probably leading to the double structures in photoluminescence spectrum. Therefore, this model gives a comprehensively new understanding on the mechanism of the structured GL band in ZnO.
Collapse
Affiliation(s)
- Honggang Ye
- Department of Physics, Shenzhen Institute of Research and Innovation, The University of Hong Kong, Pokfulam Road, Hong Kong, China.,Department of Applied Physics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Zhicheng Su
- Department of Physics, Shenzhen Institute of Research and Innovation, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Fei Tang
- Department of Physics, Shenzhen Institute of Research and Innovation, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Mingzheng Wang
- Department of Physics, Shenzhen Institute of Research and Innovation, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Guangde Chen
- Department of Applied Physics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Jian Wang
- Department of Physics, Shenzhen Institute of Research and Innovation, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Shijie Xu
- Department of Physics, Shenzhen Institute of Research and Innovation, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| |
Collapse
|
43
|
Abstract
The nature of isolated nitrogen-dopants in bulk BaO (N-BaO) and their magnetic interaction have been investigated by means of density functional theory calculations based on hybrid, self-interaction corrected functionals. A thermodynamic analysis shows that N is preferably incorporated into interstitial sites. Only at very high temperatures and under oxygen poor-conditions the formation of N dopants substitutional to O is preferred. The spin density is rather localized in both cases, as proven by the calculation of the hyperfine coupling constants of the electron spin with the nuclear spin of nitrogen. The magnetic interaction of two N defects in various configurations has been considered as a function of their distance. Different behaviors have been observed, depending on the position of the N defects and on the nature of the dominating magnetic mechanism. In any case, the computed Curie temperature is below room temperature, suggesting that RT ferromagnetism cannot be attained for this kind of doping in BaO. Finally, the interplay of oxygen vacancies with the N dopants has been studied. The inclusion of nitrogen has the effect of drastically reducing the cost to create oxygen vacancies. These in turn quench the magnetic moment of N-dopants, contributing to reducing the concentration of magnetic impurities.
Collapse
Affiliation(s)
- Elisa Albanese
- Dipartimento di Scienza dei Materiali, Università Milano Bicocca, via R. Cozzi 55, 20125 Milano, Italy.
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università Milano Bicocca, via R. Cozzi 55, 20125 Milano, Italy.
| |
Collapse
|
44
|
Proshchenko V, Dahnovsky Y. Weak d 0 ferromagnetism: Zn vacancy condensation in ZnS nanocrystals. J Phys Condens Matter 2017; 29:025803. [PMID: 27842002 DOI: 10.1088/0953-8984/29/2/025803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We provide the explanation of the large discrepancy of three orders of magnitude between the experimentally measured and theoretically calculated magnetic moments in ZnS nanocrystals. We assume that the condensation of Zn vacancies into a single droplet takes place. The energy calculations reveal that the droplet phase is more favorable than the uniformly distributed vacancy configuration. The other assumption made is that a small magnetic moment could arise at the interface between the ZnS crystal and vacancy cluster. The calculations however dismiss this hypothesis because the magnetization of the layered system also vanishes. Thus we suggest that the experimentally low magnetization values could be explained from one of the two following pictures: (a) there are two phases where the vacancy cluster with the zero magnetic moment coexists along with the other phase, in which there are uniformly distributed Zn vacancies with low concentrations or (b) there is only a single vacancy phase-a vacancy droplet being in the metastable state with a weak nonvanishing magnetic moment.
Collapse
Affiliation(s)
- Vitaly Proshchenko
- Department of Physics and Astronomy/3905, University of Wyoming, 1000 E. University Avenue, Laramie, WY 82071, USA
| | | |
Collapse
|
45
|
Il’ves VG, Sokovnin SY. Structural and Magnetic Properties of Nanopowders and Coatings of Carbon-Doped Zinc Oxide Prepared by Pulsed Electron Beam Evaporation. Journal of Nanotechnology 2017; 2017:1-11. [DOI: 10.1155/2017/4628193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
With the help of electron beam evaporation of mechanical mixtures of nonmagnetic micron powders ZnO and carbon in vacuum with the subsequent annealing of evaporation products in air at the temperature of 773 K, single-phase crystal nanopowders ZnO-C were produced with the hexagonal wurtzite structure and low content of the carbon dopant not exceeding 0.25 wt%. It was established that doping ZnO with carbon stimulates primary growth of nanoparticles along the direction 0001 in the coatings. Nanocrystal growth in coatings occurs in the same way as crystal growth in thin films, with growth anisotropy in the c-axis direction in wurtzite ZnO. Element mapping has confirmed homogeneous distribution of carbon in ZnO lattice. Ferromagnetism of single-phase crystal nanopowders ZnO-C with the hexagonal wurtzite structure and low content of the carbon dopant not exceeding 0.25 wt% was produced at room temperature. Ferromagnetic response of the doped NP ZnO-C has exceeded the ferromagnetic response of pure NP ZnO 5 times. The anhysteretic form of magnetization curves NP ZnO-C indicates aspiration of samples to superparamagnetism manifestation.
Collapse
|
46
|
Colombo E, Li W, Bhangu SK, Ashokkumar M. Chitosan microspheres as a template for TiO2and ZnO microparticles: studies on mechanism, functionalization and applications in photocatalysis and H2S removal. RSC Adv 2017. [DOI: 10.1039/c7ra01227f] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Highly efficient micron-sized photocatalysts with easy removability and recyclability features.
Collapse
Affiliation(s)
| | - Wu Li
- School of Chemistry
- University of Melbourne
- Australia
| | | | | |
Collapse
|
47
|
Abstract
The present study reports the structural, morphological, optical and magnetic properties of N ion implanted CeO2 thin films deposited by a RF magnetron sputtering technique.
Collapse
Affiliation(s)
- Pawan Kumar
- Department of Physics
- Kurukshetra University
- Kurukshetra
- India
| | - Parmod Kumar
- Materials Science Division
- Inter University Accelerator Centre
- New Delhi-110067
- India
| | - Ashish Kumar
- Materials Science Division
- Inter University Accelerator Centre
- New Delhi-110067
- India
| | - Indra Sulania
- Materials Science Division
- Inter University Accelerator Centre
- New Delhi-110067
- India
| | - F. Chand
- Department of Physics
- Kurukshetra University
- Kurukshetra
- India
| | - K. Asokan
- Materials Science Division
- Inter University Accelerator Centre
- New Delhi-110067
- India
| |
Collapse
|
48
|
Jäppinen L, Jalkanen T, Sieber B, Addad A, Heinonen M, Kukk E, Radevici I, Paturi P, Peurla M, Shahbazi MA, Santos HA, Boukherroub R, Santos H, Lastusaari M, Salonen J. Enhanced Photoluminescence in Acetylene-Treated ZnO Nanorods. Nanoscale Res Lett 2016; 11:413. [PMID: 27644239 PMCID: PMC5028353 DOI: 10.1186/s11671-016-1627-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Accepted: 09/09/2016] [Indexed: 06/06/2023]
Abstract
Zinc oxide (ZnO) nanorods were manufactured using the aqueous chemical growth (ACG) method, and the effect of thermal acetylene treatment on their morphology, chemical composition, and optical properties was investigated. Changes in the elemental content of the treated rods were found to be different than in previous reports, possibly due to the different defect concentrations in the samples, highlighting the importance of synthesis method selection for the process. Acetylene treatment resulted in a significant improvement of the ultraviolet photoluminescence of the rods. The greatest increase in emission intensity was recorded on ZnO rods treated at the temperature of 825 °C. The findings imply that the changes brought on by the treatment are limited to the surface of the ZnO rods.
Collapse
Affiliation(s)
- Luke Jäppinen
- Department of Physics and Astronomy, University of Turku, FI-20014 Turku, Finland
| | - Tero Jalkanen
- Department of Physics and Astronomy, University of Turku, FI-20014 Turku, Finland
| | - Brigitte Sieber
- Unité Matériaux et Transformations, Université Lille 1, 59655 Villeneuve d’Ascq, France
| | - Ahmed Addad
- Unité Matériaux et Transformations, Université Lille 1, 59655 Villeneuve d’Ascq, France
| | - Markku Heinonen
- Department of Physics and Astronomy, University of Turku, FI-20014 Turku, Finland
| | - Edwin Kukk
- Department of Physics and Astronomy, University of Turku, FI-20014 Turku, Finland
| | - Ivan Radevici
- Department of Physics and Astronomy, University of Turku, FI-20014 Turku, Finland
| | - Petriina Paturi
- Department of Physics and Astronomy, University of Turku, FI-20014 Turku, Finland
| | - Markus Peurla
- Institute of Biomedicine, University of Turku, FI-20014 Turku, Finland
| | - Mohammad-Ali Shahbazi
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, FI-00014 Helsinki, Finland
| | - Hélder A. Santos
- Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, FI-00014 Helsinki, Finland
| | - Rabah Boukherroub
- Institut d’Electronique, de Microélectronique et de Nanotechnologie (IEMN), Université Lille 1, 59652 Villeneuve d’Ascq, France
| | - Hellen Santos
- Department of Chemistry, University of Turku, FI-20014 Turku, Finland
| | - Mika Lastusaari
- Department of Chemistry, University of Turku, FI-20014 Turku, Finland
| | - Jarno Salonen
- Department of Physics and Astronomy, University of Turku, FI-20014 Turku, Finland
| |
Collapse
|
49
|
Saadaoui H, Luo X, Salman Z, Cui XY, Bao NN, Bao P, Zheng RK, Tseng LT, Du YH, Prokscha T, Suter A, Liu T, Wang YR, Li S, Ding J, Ringer SP, Morenzoni E, Yi JB. Intrinsic Ferromagnetism in the Diluted Magnetic Semiconductor Co:TiO_{2}. Phys Rev Lett 2016; 117:227202. [PMID: 27925730 DOI: 10.1103/physrevlett.117.227202] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Indexed: 06/06/2023]
Abstract
Here we present a study of magnetism in Co_{0.05}Ti_{0.95}O_{2-δ} anatase films grown by pulsed laser deposition under a variety of oxygen partial pressures and deposition rates. Energy-dispersive spectrometry and transmission electron microscopy analyses indicate that a high deposition rate leads to a homogeneous microstructure, while a very low rate or postannealing results in cobalt clustering. Depth resolved low-energy muon spin rotation experiments show that films grown at a low oxygen partial pressure (≈10^{-6} torr) with a uniform structure are fully magnetic, indicating intrinsic ferromagnetism. First principles calculations identify the beneficial role of low oxygen partial pressure in the realization of uniform carrier-mediated ferromagnetism. This work demonstrates that Co:TiO_{2} is an intrinsic diluted magnetic semiconductor.
Collapse
Affiliation(s)
- H Saadaoui
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - X Luo
- School of Materials Science and Engineering, UNSW, Sydney, New South Wales 2052, Australia
| | - Z Salman
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - X Y Cui
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - N N Bao
- Department of Materials Science and Engineering, National University of Singapore, 119260, Singapore
| | - P Bao
- School of Physics, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - R K Zheng
- School of Physics, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - L T Tseng
- School of Materials Science and Engineering, UNSW, Sydney, New South Wales 2052, Australia
| | - Y H Du
- Institute of Chemical and Engineering Science, Agency for Science, Technology and Research (A*STAR), 1 Pesek Road, Jurong Island, 627833, Singapore
| | - T Prokscha
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - A Suter
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - T Liu
- ANKA, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany
| | - Y R Wang
- School of Materials Science and Engineering, UNSW, Sydney, New South Wales 2052, Australia
| | - S Li
- School of Materials Science and Engineering, UNSW, Sydney, New South Wales 2052, Australia
| | - J Ding
- Department of Materials Science and Engineering, National University of Singapore, 119260, Singapore
| | - S P Ringer
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, New South Wales 2006, Australia
- The Australian Institute for Nanoscale Science and Technology, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - E Morenzoni
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - J B Yi
- School of Materials Science and Engineering, UNSW, Sydney, New South Wales 2052, Australia
| |
Collapse
|
50
|
Chakraborty B, Ramaniah LM. Room temperature d (0) ferromagnetism in hole doped Y2O3: widening the choice of host to tailor DMS. J Phys Condens Matter 2016; 28:336001. [PMID: 27351301 DOI: 10.1088/0953-8984/28/33/336001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Transition metal-free-ferromagnetism in diluted magnetic semiconductors (DMS) is of much current interest in view of the search for more efficient DMS materials for spintronics applications. Our DFT results predict for the first time, that impurities from group1A (Li(+), Na(+), K(+)) doped on Y2O3 can induce a magnetic signature with a magnetic moment around 2.0 μ B per defect at hole concentrations around 1.63 × 10(21) cm(-3), which is one order less than the critical hole density of ZnO with ferromagnetic coupling large enough to promote room temperature ferromagnetism. The induction of room temperature ferromagnetism by hole doping with an impurity atom from group 1A, which injects two holes per defect in the system, implies that the recommendation of three holes per defect given in the literature, which puts a restriction on the choice of host material and the impurity, is not a necessary criterion for hole induced room temperature ferromagnetism. DFT simulations with the generalized gradient approximation (GGA), confirmed by the more sophisticated hybrid functional, Heyd-Scuseria-Ernzerhof (HSE06), predict that the magnetic moment is mostly contributed by O atoms surrounding the impurity atom and the magnetic moment scale up with impurity concentration which is a positive indicator for practical applications. We quantitatively and extensively demonstrate through the analysis of the density of states and ferromagnetic coupling that the Stoner criterion is satisfied by pushing the Fermi level inside the valence band to activate room temperature ferromagnetism. The stability of the structure and the persistence of ferromagnetism at room temperature were demonstrated by ab initio MD simulations and computation of Curie temperature through the mean field approximation. This study widens the choice of host oxides to tailor DMS for spintronics applications.
Collapse
Affiliation(s)
- Brahmananda Chakraborty
- High Pressure & Synchroton Radiation Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400085, India
| | | |
Collapse
|