1
|
Evstafieva M, Redkin A, Roshchupkin D, Rudneva T, Yakimov EE. Influence of Exposure to a Wet Atmosphere on the UV-Sensing Characteristics of ZnO Nanorod Arrays. MATERIALS (BASEL, SWITZERLAND) 2024; 17:1053. [PMID: 38473527 DOI: 10.3390/ma17051053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 02/19/2024] [Accepted: 02/22/2024] [Indexed: 03/14/2024]
Abstract
Zinc oxide is a promising material for the creation of various types of sensors, in particular UV detectors. In this work, arrays of ordered nanorods were grown by chemical vapor deposition. The effect of environmental humidity on the sensing properties of zinc oxide nanorod arrays was investigated, and a prototype UV sensor using indium as an ohmic contact was developed. UV photoresponses were measured for the samples stored in dry and wet atmospheres. The increase in sensitivity and response of the ZnO nanorod arrays was observed after prolonged exposure to a wet atmosphere. A model was proposed to explain this effect. This is due to the formation of hydroxyl groups on the surface of zinc oxide nanorods, which is confirmed by FTIR spectroscopy data. For the first time, it has been shown that after storage in a wet atmosphere, the sensory properties of the structure remain stable regardless of the ambient humidity.
Collapse
Affiliation(s)
- Maria Evstafieva
- Institute of Microelectronics Technology RAS, 6 Academician Ossipyan Str., 142432 Chernogolovka, Russia
| | - Arcady Redkin
- Institute of Microelectronics Technology RAS, 6 Academician Ossipyan Str., 142432 Chernogolovka, Russia
| | - Dmitry Roshchupkin
- Institute of Microelectronics Technology RAS, 6 Academician Ossipyan Str., 142432 Chernogolovka, Russia
| | - Tatyana Rudneva
- Institute of Microelectronics Technology RAS, 6 Academician Ossipyan Str., 142432 Chernogolovka, Russia
| | - Eugene E Yakimov
- Institute of Microelectronics Technology RAS, 6 Academician Ossipyan Str., 142432 Chernogolovka, Russia
| |
Collapse
|
2
|
Huang K, Lu J, Li D, Chen X, Jin D, Jin H. Au- or Ag-Decorated ZnO-Rod/rGO Nanocomposite with Enhanced Room-Temperature NO 2-Sensing Performance. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2370. [PMID: 37630954 PMCID: PMC10459478 DOI: 10.3390/nano13162370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Revised: 08/04/2023] [Accepted: 08/15/2023] [Indexed: 08/27/2023]
Abstract
To improve the gas sensitivity of reduced oxide graphene (rGO)-based NO2 room-temperature sensors, different contents (0-3 wt%) of rGO, ZnO rods, and noble metal nanoparticles (Au or Ag NPs) were synthesized to construct ternary hybrids that combine the advantages of each component. The prepared ZnO rods had a diameter of around 200 nm and a length of about 2 μm. Au or Ag NPs with diameters of 20-30 nm were loaded on the ZnO-rod/rGO hybrid. It was found that rGO simply connects the monodispersed ZnO rods and does not change the morphology of ZnO rods. In addition, the rod-like ZnO prevents rGO stacking and makes nanocomposite-based ZnO/rGO achieve a porous structure, which facilitates the diffusion of gas molecules. The sensors' gas-sensing properties for NO2 were evaluated. The results reveal that Ag@ZnO rods-2% rGO and Au@ZnO rods-2% rGO perform better in low concentrations of NO2 gas, with greater response and shorter recovery time at the ambient temperature. The response and recovery times with 15 ppm NO2 were 132 s, 139 s and 108 s, 120 s, and the sensitivity values were 2.26 and 2.87, respectively. The synergistic impact of ZnO and Au (Ag) doping was proposed to explain the improved gas sensing. The p-n junction formed on the ZnO and rGO interface and the catalytic effects of Au (Ag) NPs are the main reasons for the enhanced sensitivity of Au (Ag)@ZnO rods-2% rGO.
Collapse
Affiliation(s)
| | | | | | | | | | - Hongxiao Jin
- College of Materials Science and Engineering, China Jiliang University, Hangzhou 310018, China
| |
Collapse
|
3
|
Yu L, Cai W, Wang L, Lee CY, Sun S, Xiao Y, Shen KC, Chen C. Three-Dimensional crystallized ZnO crosslinked nanowire structure. INORG CHEM COMMUN 2022. [DOI: 10.1016/j.inoche.2022.109413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
4
|
Villafuerte J, Sarigiannidou E, Donatini F, Kioseoglou J, Chaix-Pluchery O, Pernot J, Consonni V. Modulating the growth of chemically deposited ZnO nanowires and the formation of nitrogen- and hydrogen-related defects using pH adjustment. NANOSCALE ADVANCES 2022; 4:1793-1807. [PMID: 36132162 PMCID: PMC9417859 DOI: 10.1039/d1na00785h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 02/22/2022] [Indexed: 06/15/2023]
Abstract
ZnO nanowires (NWs) grown by chemical bath deposition (CBD) have received great interest for nanoscale engineering devices, but their formation in aqueous solution containing many impurities needs to be carefully addressed. In particular, the pH of the CBD solution and its effect on the formation mechanisms of ZnO NWs and of nitrogen- and hydrogen-related defects in their center are still unexplored. By adjusting its value in a low- and high-pH region, we show the latent evolution of the morphological and optical properties of ZnO NWs, as well as the modulated incorporation of nitrogen- and hydrogen-related defects in their center using Raman and cathodoluminescence spectroscopy. The increase in pH is related to the increase in the oxygen chemical potential (μ O), for which the formation energy of hydrogen in bond-centered sites (HBC) and VZn-NO-H defect complexes is found to be unchanged, whereas the formation energy of zinc vacancy (VZn) and zinc vacancy-hydrogen (VZn-nH) complexes steadily decreases as shown from density-functional theory calculations. Revealing that these VZn-related defects are energetically favorable to form as μ O is increased, ZnO NWs grown in the high-pH region are found to exhibit a higher density of VZn-nH defect complexes than ZnO NWs grown in the low-pH region. Annealing at 450 °C under an oxygen atmosphere helps tuning the optical properties of ZnO NWs by reducing the density of HBC and VZn-related defects, while activating the formation of VZn-NO-H defect complexes. These findings show the influence of pH on the nature of Zn(ii) species, the electrostatic interactions between these species and ZnO NW surfaces, and the formation energy of the involved defects. They emphasize the crucial role of the pH of the CBD solution and open new possibilities for simultaneously engineering the morphology of ZnO NWs and the formation of nitrogen- and hydrogen-related defects.
Collapse
Affiliation(s)
- José Villafuerte
- Université Grenoble Alpes, CNRS, Grenoble INP, LMGP F-38000 Grenoble France
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut NEEL F-38000 Grenoble France
| | | | - Fabrice Donatini
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut NEEL F-38000 Grenoble France
| | - Joseph Kioseoglou
- Physics Department, Aristotle University of Thessaloniki 54124 Thessaloniki Greece
| | | | - Julien Pernot
- Université Grenoble Alpes, CNRS, Grenoble INP, Institut NEEL F-38000 Grenoble France
| | - Vincent Consonni
- Université Grenoble Alpes, CNRS, Grenoble INP, LMGP F-38000 Grenoble France
| |
Collapse
|
5
|
Emergence and Evolution of Crystallization in TiO 2 Thin Films: A Structural and Morphological Study. NANOMATERIALS 2021; 11:nano11061409. [PMID: 34073645 PMCID: PMC8227354 DOI: 10.3390/nano11061409] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 05/16/2021] [Accepted: 05/19/2021] [Indexed: 12/03/2022]
Abstract
Among all transition metal oxides, titanium dioxide (TiO2) is one of the most intensively investigated materials due to its large range of applications, both in the amorphous and crystalline forms. We have produced amorphous TiO2 thin films by means of room temperature ion-plasma assisted e-beam deposition, and we have heat-treated the samples to study the onset of crystallization. Herein, we have detailed the earliest stage and the evolution of crystallization, as a function of both the annealing temperature, in the range 250–1000 °C, and the TiO2 thickness, varying between 5 and 200 nm. We have explored the structural and morphological properties of the as grown and heat-treated samples with Atomic Force Microscopy, Scanning Electron Microscopy, X-ray Diffractometry, and Raman spectroscopy. We have observed an increasing crystallization onset temperature as the film thickness is reduced, as well as remarkable differences in the crystallization evolution, depending on the film thickness. Moreover, we have shown a strong cross-talking among the complementary techniques used displaying that also surface imaging can provide distinctive information on material crystallization. Finally, we have also explored the phonon lifetime as a function of the TiO2 thickness and annealing temperature, both ultimately affecting the degree of crystallinity.
Collapse
|
6
|
Singh MP, Mandal M, Sethupathi K, Rao MSR, Nayak PK. Study of Thermometry in Two-Dimensional Sb 2Te 3 from Temperature-Dependent Raman Spectroscopy. NANOSCALE RESEARCH LETTERS 2021; 16:22. [PMID: 33537903 PMCID: PMC7859149 DOI: 10.1186/s11671-020-03463-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 12/11/2020] [Indexed: 06/12/2023]
Abstract
Discovery of two-dimensional (2D) topological insulators (TIs) demonstrates tremendous potential in the field of thermoelectric since the last decade. Here, we have synthesized 2D TI, Sb2Te3 of various thicknesses in the range 65-400 nm using mechanical exfoliation and studied temperature coefficient in the range 100-300 K using micro-Raman spectroscopy. The temperature dependence of the peak position and line width of phonon modes have been analyzed to determine the temperature coefficient, which is found to be in the order of 10-2 cm-1/K, and it decreases with a decrease in Sb2Te3 thickness. Such low-temperature coefficient would favor to achieve a high figure of merit (ZT) and pave the way to use this material as an excellent candidate for thermoelectric materials. We have estimated the thermal conductivity of Sb2Te3 flake with the thickness of 115 nm supported on 300-nm SiO2/Si substrate which is found to be ~ 10 W/m-K. The slightly higher thermal conductivity value suggests that the supporting substrate significantly affects the heat dissipation of the Sb2Te3 flake.
Collapse
Affiliation(s)
- Manavendra P Singh
- Department of Physics and Materials Science Research Centre, Indian Institute of Technology Madras, Chennai, 600 036, India
| | - Manab Mandal
- Department of Physics, Indian Institute of Technology Madras, Chennai, 600 036, India
| | - K Sethupathi
- Department of Physics, Indian Institute of Technology Madras, Chennai, 600 036, India
| | - M S Ramachandra Rao
- Department of Physics and Materials Science Research Centre, Indian Institute of Technology Madras, Chennai, 600 036, India
- Nano Functional Materials Technology Centre, Indian Institute of Technology Madras, Chennai, 600 036, India
| | - Pramoda K Nayak
- Department of Physics and Materials Science Research Centre, Indian Institute of Technology Madras, Chennai, 600 036, India.
| |
Collapse
|
7
|
Temperature-Dependent Raman Scattering of Large Size Hexagonal Bi2Se3 Single-Crystal Nanoplates. APPLIED SCIENCES-BASEL 2018. [DOI: 10.3390/app8101794] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Bi 2 Se 3 has extensive application as thermoelectric materials. Here, large-scale Bi 2 Se 3 single-crystal hexagonal nanoplates with size 7.50–10.0 μ m were synthesized successfully by hydrothermal method. X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM) were used to characterize the Bi 2 Se 3 nanoplates, which confirm the single-crystal quality and smooth surface morphology with large size. Micro-Raman spectra over a temperature range of 83–603 K were furthermore used to investigate the lattice dynamics of Bi 2 Se 3 nanoplates. Both 2A g 1 and 1E g 2 modes shift evidently with reduced temperature. The line shape demonstrates a significant broadening of full width at half maximum (FWHM) and red-shift of frequency with increased temperature. The temperature coefficient of A 1 g 1 , E g 2 , A 1 g 2 modes were determined to be −1.258 × 10 − 2 cm − 1 /K, −1.385 × 10 − 2 cm − 1 /K, −2.363 × 10 − 2 cm − 1 /K, respectively. Such low temperature coefficient may favor the obtaining of a high figure of merit (ZT) and indicate that Bi 2 Se 3 nanoplates were used as excellent candidates of thermoelectric materials.
Collapse
|
8
|
Influence of different solvents on portrayal and photocatalytic activity of tin-doped zinc oxide nanoparticles. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.03.074] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
9
|
Sahoo SK, Mangal S, Mishra D, Singh UP, Kumar P. 100 keV H +
ion irradiation of as-deposited Al-doped ZnO thin films: An interest in tailoring surface morphology for sensor applications. SURF INTERFACE ANAL 2018. [DOI: 10.1002/sia.6461] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Susanta Kumar Sahoo
- School of Applied Sciences; KIIT (Deemed to be University); Bhubaneswar 751024 Odisha India
| | - Sutanu Mangal
- School of Applied Sciences; KIIT (Deemed to be University); Bhubaneswar 751024 Odisha India
| | - D.K. Mishra
- Department of Physics, Faculty of Engineering and Technology (ITER); Siksha ‘O’ Anusandhan (Deemed to be University); Bhubaneswar 751030 Odisha India
| | - Udai P. Singh
- School of Electronics Engineering; KIIT (Deemed to be University); Bhubaneswar 751024 Odisha India
| | - Pravin Kumar
- Inter University Accelerator Centre; Aruna Asaf Ali Marg New Delhi 110067 India
| |
Collapse
|
10
|
Influence of reduction time of catalyst on methanol synthesis via CO 2 hydrogenation using Cu–Zn/N-rGO investigated by in situ XANES. J Taiwan Inst Chem Eng 2017. [DOI: 10.1016/j.jtice.2017.08.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
11
|
Hassanpour A, Guo P, Shen S, Bianucci P. The effect of cation doping on the morphology, optical and structural properties of highly oriented wurtzite ZnO-nanorod arrays grown by a hydrothermal method. NANOTECHNOLOGY 2017; 28:435707. [PMID: 28786398 DOI: 10.1088/1361-6528/aa849d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Undoped and C-doped (C: Mg2+, Ni2+, Mn2+, Co2+, Cu2+, Cr3+) ZnO nanorods were synthesized by a hydrothermal method at temperatures as low as 60 °C. The effect of doping on the morphology of the ZnO nanorods was visualized by taking their cross section and top SEM images. The results show that the size of nanorods was increased in both height and diameter by cation doping. The crystallinity change of the ZnO nanorods due to each doping element was thoroughly investigated by an x-ray diffraction (XRD). The XRD patterns show that the wurtzite crystal structure of ZnO nanorods was maintained after cation addition. The optical Raman-active modes of undoped and cation-doped nanorods were measured with a micro-Raman setup at room temperature. The surface chemistry of samples was investigated by x-ray photoelectron spectroscopy and energy-dispersive x-ray spectroscopy. Finally, the effect of each cation dopant on band-gap shift of the ZnO nanorods was investigated by a photoluminescence setup at room temperature. Although the amount of dopants (Mg2+, Ni2+, and Co2+) was smaller than the amount of Mn2+, Cu2+, and Cr3+ in the nanorods, their effect on the band structure of the ZnO nanorods was profound. The highest band-gap shift was achieved for a Co-doped sample, and the best crystal orientation was for Mn-doped ZnO nanorods. Our results can be used as a comprehensive reference for engineering of the morphological, structural and optical properties of cation-doped ZnO nanorods by using a low-temperature synthesis as an economical mass-production approach.
Collapse
Affiliation(s)
- A Hassanpour
- Department of Physics, Concordia University, Montreal, QC, Canada. International Research Center for Renewable Energy (IRCRE), School of Energy & Power Engineering, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | | | | | | |
Collapse
|
12
|
|
13
|
Gerigk M, Ehrenreich P, Wagner MR, Wimmer I, Reparaz JS, Torres CMS, Schmidt-Mende L, Polarz S. Nanoparticle shape anisotropy and photoluminescence properties: Europium containing ZnO as a Model Case. NANOSCALE 2015; 7:16969-16982. [PMID: 26415672 DOI: 10.1039/c5nr02550h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The precise control over electronic and optical properties of semiconductor (SC) materials is pivotal for a number of important applications like in optoelectronics, photocatalysis or in medicine. It is well known that the incorporation of heteroelements (doping as a classical case) is a powerful method for adjusting and enhancing the functionality of semiconductors. Independent from that, there already has been a tremendous progress regarding the synthesis of differently sized and shaped SC nanoparticles, and quantum-size effects are well documented experimentally and theoretically. Whereas size and shape control of nanoparticles work fairly well for the pure compounds, the presence of a heteroelement is problematic because the impurities interfere strongly with bottom up approaches applied for the synthesis of such particles, and effects are even stronger, when the heteroelement is aimed to be incorporated into the target lattice for chemical doping. Therefore, realizing coincident shape control of nanoparticle colloids and their doping still pose major difficulties. Due to a special mechanism of the emulsion based synthesis method presented here, involving a gelation of emulsion droplets prior to crystallization of shape-anisotropic ZnO nanoparticles, heteroelements can be effectively entrapped inside the lattice. Different nanocrystal shapes such as nanorods, -prisms, -plates, and -spheres can be obtained, determined by the use of certain emulsification agents. The degree of morphologic alterations depends on the type of incorporated heteroelement M(n+), concentration, and it seems that some shapes are more tolerant against doping than others. Focus was then set on the incorporation of Eu(3+) inside the ZnO particles, and it was shown that nanocrystal shape and aspect ratios could be adjusted while maintaining a fixed dopant level. Special PL properties could be observed implying energy transfer from ZnO excited near its band-gap (3.3 eV) to the Eu(3+) states mediated by defect luminescence of the nanoparticles. Indications for an influence of shape on photoluminescence (PL) properties were found. Finally, rod-like Eu@ZnO colloids were used as tracers to investigate their uptake into biological samples like HeLa cells. The PL was sufficient for identifying green and red emission under visible light excitation.
Collapse
Affiliation(s)
- Melanie Gerigk
- University of Konstanz, Universitaetsstr. 10, 78464 Konstanz, Germany.
| | | | | | | | | | | | | | | |
Collapse
|
14
|
Pereira ALJ, Gomis O, Sans JA, Pellicer-Porres J, Manjón FJ, Beltran A, Rodríguez-Hernández P, Muñoz A. Pressure effects on the vibrational properties of α-Bi(2)O(3): an experimental and theoretical study. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:225401. [PMID: 24810681 DOI: 10.1088/0953-8984/26/22/225401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We report an experimental and theoretical high-pressure study of the vibrational properties of synthetic monoclinic bismuth oxide (α-Bi(2)O(3): ), also known as mineral bismite. The comparison of Raman scattering measurements and theoretical lattice-dynamics ab initio calculations is key to understanding the complex vibrational properties of bismite. On one hand, calculations help in the symmetry assignment of phonons and to discover the phonon interactions taking place in this low-symmetry compound, which shows considerable phonon anticrossings; and, on the other hand, measurements help to validate the accuracy of first-principles calculations relating to this compound. We have also studied the pressure-induced amorphization (PIA) of synthetic bismite occurring around 20 GPa and showed that it is reversible below 25 GPa. Furthermore, a partial temperature-induced recrystallization (TIR) of the amorphous sample can be observed above 20 GPa upon heating to 200°C, thus evidencing that PIA at room temperature occurs because of the inability of the α phase to undergo a phase transition to a high-pressure phase. Raman scattering measurements of the TIR sample at room temperature during pressure release have been performed. The interpretation of these results in the light of ab initio calculations of the candidate phases at high pressures has allowed us to tentatively attribute the TIR phase to the recently found high-pressure hexagonal HPC phase and to discuss its lattice dynamics.
Collapse
Affiliation(s)
- A L J Pereira
- Departamento de Física Aplicada, Instituto de Diseño para la Fabricación y Producción Automatizada, MALTA Consolider Team, Universitat Politècnica de València, 46022 Valencia, Spain
| | | | | | | | | | | | | | | |
Collapse
|
15
|
Gedamu D, Paulowicz I, Kaps S, Lupan O, Wille S, Haidarschin G, Mishra YK, Adelung R. Rapid fabrication technique for interpenetrated ZnO nanotetrapod networks for fast UV sensors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:1541-50. [PMID: 24249633 DOI: 10.1002/adma.201304363] [Citation(s) in RCA: 159] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 10/10/2013] [Indexed: 05/11/2023]
Abstract
Two flame-based synthesis methods are presented for fabricating ZnO-nanostructure-based UV photodetectors: burner flame transport synthesis (B-FTS)and crucible flame transport synthesis (C-FTS). B-FTS allows rapid growth of ZnO nanotetrapods and in situ bridging of them into electrical contacts. The photo detector made from interconnected ZnO nanotetrapod networks exhibits fast response/recovery times and a high current ratio under UV illumination.
Collapse
Affiliation(s)
- Dawit Gedamu
- Functional Nanomaterials, Institute for Materials Science, University of Kiel, Kaiser Strasse 2, D-24143, Kiel, Germany
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Dielectric properties and Raman spectra of ZnO from a first principles finite-differences/finite-fields approach. Sci Rep 2013; 3:2999. [PMID: 24141391 PMCID: PMC3801111 DOI: 10.1038/srep02999] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Accepted: 10/02/2013] [Indexed: 11/09/2022] Open
Abstract
Using first principles calculations based on density functional theory and a coupled finite-fields/finite-differences approach, we study the dielectric properties, phonon dispersions and Raman spectra of ZnO, a material whose internal polarization fields require special treatment to correctly reproduce the ground state electronic structure and the coupling with external fields. Our results are in excellent agreement with existing experimental measurements and provide an essential reference for the characterization of crystallinity, composition, piezo- and thermo-electricity of the plethora of ZnO-derived nanostructured materials used in optoelectronics and sensor devices.
Collapse
|
17
|
Ameen S, Shaheer Akhtar M, Shin HS. Highly sensitive hydrazine chemical sensor fabricated by modified electrode of vertically aligned zinc oxide nanorods. Talanta 2012; 100:377-83. [DOI: 10.1016/j.talanta.2012.08.001] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 07/31/2012] [Accepted: 08/02/2012] [Indexed: 11/28/2022]
|
18
|
Venkatesh PS, Purushothaman V, Muthu SE, Arumugam S, Ramakrishnan V, Jeganathan K, Ramamurthi K. Role of point defects on the enhancement of room temperature ferromagnetism in ZnO nanorods. CrystEngComm 2012. [DOI: 10.1039/c2ce25098e] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
19
|
Sundara Venkatesh P, Ramakrishnan V, Jeganathan K. Vertically aligned indium doped zinc oxide nanorods for the application of nanostructured anodes by radio frequency magnetron sputtering. CrystEngComm 2012. [DOI: 10.1039/c2ce25220a] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
20
|
Ameen S, Akhtar MS, Kim YS, Yang OB, Shin HS. Influence of seed layer treatment on low temperature grown ZnO nanotubes: Performances in dye sensitized solar cells. Electrochim Acta 2011. [DOI: 10.1016/j.electacta.2010.10.085] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
21
|
Shinde S, Shinde P, Sathe V, Barman S, Bhosale C, Rajpure K. Electron–phonon interaction and size effect study in catalyst based zinc oxide thin films. J Mol Struct 2010. [DOI: 10.1016/j.molstruc.2010.09.026] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
22
|
Li JW, Yang LW, Zhou ZF, Liu XJ, Xie GF, Pan Y, Sun CQ. Mechanically stiffened and thermally softened Raman modes of ZnO crystal. J Phys Chem B 2010; 114:1648-51. [PMID: 20055382 DOI: 10.1021/jp909952c] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An analytical form connecting the energy shift of Raman modes directly to the bonding identities (order, nature, length, energy) of a specimen and the response of the bonding identities to the applied stimuli of temperature and pressure was presented for a deeper understanding of the atomistic origin of the ZnO Raman shift. Theoretical reproduction based on the BOLS correlation theory [Sun, C. Q. Prog. Solid State Chem. 2007, 35, 1] and the local bond average (LBA) approach [Sun, C. Q. Prog. Mater. Sci. 2009, 54, 179] of the measurements revealed that the thermally softened ZnO Raman modes arise from bond expansion and bond weakening due to vibration and that the pressure-stiffened Raman modes result from bond compression and bond strengthening due to mechanical work hardening. The developed approach could be useful in generalizing the lattice dynamics directly to the process of vibration and relaxation of a representative bond of the specimen under external stimuli.
Collapse
Affiliation(s)
- J W Li
- Institute for Quantum Engineering and Micro-Nano Energy Technology, Key Laboratory of Low-Dimensional Materials and Application Technologies, and Faculty of Materials and Optoelectronic Physics, Xiangtan University, Hunan 411105, China
| | | | | | | | | | | | | |
Collapse
|
23
|
Cheng B, Jiao J, Sun W, Tian B, Xiao Y, Lei S. Lattice variation and Raman spectroscopy in hierarchical heterostructures of zinc antimonate nanoislands on ZnO nanobelts. NANOTECHNOLOGY 2010; 21:025704. [PMID: 19955602 DOI: 10.1088/0957-4484/21/2/025704] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In ZnO hierarchical heterostructures of zinc antimonate nanoislands on ZnO nanobelts, the substitution of Sb(5+) for Zn(2+) induces lattice contraction and a variation in vacancy defects, and moreover the preferential accumulation and segregation of Sb in [001] planes results in the intense perturbation of atomic motion in the a-b plane. Under nonresonant conditions, nonpolar E(2)(high) and polar quasi-longitudinal optic (LO) modes decrease in frequency due to finite-size and phonon confinement effects. Under resonant conditions, localized excitons can ionize to free carriers and form plasmons at higher excitation power density, resulting in the transformation of scattering coupling from localized exciton-LO-phonon to LO-phonon-plasmon. The intensity ratio of 2LO/1LO decreases and multiphonon scattering shows a decrease in frequency with unequal neighboring interval, and moreover the scattering coupling between the continuum of electron-hole plasmon and the discrete LO phonons causes an asymmetric lineshape.
Collapse
Affiliation(s)
- Baochang Cheng
- Institute for Advanced Studying, School of Materials Science and Engineering, Nanchang University, Nanchang, People's Republic of China.
| | | | | | | | | | | |
Collapse
|
24
|
Matsumoto K, Adachi Y, Sakaguchi I, Ohashi N, Haneda H. Preparation and characterization of Zn18O/Zn16O isotope heterostructure thin films. Ann Ital Chir 2010. [DOI: 10.1016/j.jeurceramsoc.2009.06.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
25
|
Rout CS, Rao CNR. Electroluminescence and rectifying properties of heterojunction LEDs based on ZnO nanorods. NANOTECHNOLOGY 2008; 19:285203. [PMID: 21828727 DOI: 10.1088/0957-4484/19/28/285203] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
n-ZnO NR/p-Si and n-ZnO NR/p-PEDOT/PSS heterojunction light-emitting diodes (LEDs) have been fabricated with ZnO nanorods (NRs) grown by a low-temperature method as well as by employing pulsed laser deposition (PLD). The low-temperature method involves growing the ZnO nanorods by the reaction of water with zinc metal. The current-voltage (I-V) characteristics of the heterojunctions show good rectifying diode characteristics. The electroluminescence (EL) spectra of the nanorods show an emission band at around 390 nm and defect related bands in the 400-550 nm region. Room-temperature electroluminescence is detected under forward bias for both the heterostructures. With the low-temperature grown nanorods, the defect related bands in the 400-550 nm range are more intense in the EL spectra, whereas with the PLD grown nanorods, only the 390 nm band is prominent.
Collapse
Affiliation(s)
- Chandra Sekhar Rout
- Chemistry and Physics of Materials Unit, DST Unit on Nanoscience and CSIR Centre of Excellence in Chemistry, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur PO, Bangalore-5600 64, India
| | | |
Collapse
|
26
|
Abstract
Pressure (P) derivatives of thermal conductivity (k) and thermal diffusivity (D) are important to geophysics but are difficult to measure accurately because minerals, being hard and partially transparent, likely incur systematic errors through thermal losses at interfaces and spurious radiative transfer. To evaluate accuracy, repeat experiments for olivine [(Mg(0.9)Fe(0.1))(2)SiO4], quartz (SiO2), and NaCl are examined in detail: these and other data on electrical insulators are compared with theory. At ambient conditions, D is underestimated in proportion to the number of contacts. As temperature (T) increases, spurious radiative transfer more than offsets contact loss. Compression of pore space and contact losses affect pressure derivatives, but these seem independent of T. Accurate (+/-2%) values of D(T) at 1 atm are obtained with the contact-free, laser-flash method. Other optical techniques do not pinpoint D but provide useful pressure derivatives. Published data on (partial differential)(lnk)/(partial differential)P at ambient conditions agree roughly with all available models, the simplest of which predicts (partial differential)(lnk)/(partial differential)P approximately (partial differential)(lnK(T))/(partial differential)P, where K(T) is the bulk modulus. However, derivatives verified by multiple measurements are reproduced accurately only by the damped harmonic oscillator model. An improved database is needed to refine this model and to confidently extrapolate these difficult measurements to geophysically relevant conditions.
Collapse
Affiliation(s)
- Anne M Hofmeister
- Department of Earth and Planetary Sciences, Washington University, St. Louis, MO 63130, USA.
| |
Collapse
|
27
|
Hauschild R, Priller H, Decker M, Brückner J, Kalt H, Klingshirn C. Temperature dependent band gap and homogeneous line broadening of the exciton emission in ZnO. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/pssc.200564643] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
28
|
Xu SJ, Xiong SJ, Shi SL. Resonant coupling of bound excitons with LO phonons in ZnO: Excitonic polaron states and Fano interference. J Chem Phys 2005; 123:221105. [PMID: 16375462 DOI: 10.1063/1.2140701] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report on a photoluminescence observation of robust excitonic polarons due to resonant coupling of exciton and longitudinal optical (LO) phonon as well as Fano-type interference in high quality ZnO crystal. At low enough temperatures, resonant coupling of excitons and LO phonons leads to not only traditional Stokes lines (SLs) but also up to second-order anti-Stokes lines (ASLs) besides the zero-phonon line (ZPL). The SLs and ASLs are found to be not mirror symmetric with respect to the ZPL, strongly suggesting that they are from different coupling states of exciton and phonons. Besides these spectral features showing the quasiparticle properties of exciton-phonon coupling system, the first-order SL is found to exhibit characteristic Fano lineshape, caused by quantum interference between the LO components of excitonic polarons and the continuous phonon bath. These findings lead to a new insight into fundamental effects of exciton-phonon interactions.
Collapse
Affiliation(s)
- S J Xu
- Department of Physics and HKU-CAS Joint Laboratory on New Materials, The University of Hong Kong, Hong Kong, China.
| | | | | |
Collapse
|