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Kumari A, Chaudhary AK, Venkatesh M. Linear and nonlinear temperature-dependent transmission/absorption characteristics of cadmium telluride crystal for terahertz generation. APPLIED OPTICS 2020; 59:3417-3421. [PMID: 32400454 DOI: 10.1364/ao.366208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Accepted: 03/07/2020] [Indexed: 06/11/2023]
Abstract
This paper reports on the temperature-dependent investigation of linear and nonlinear transmission/absorption characteristics of CdTe crystal in the 300-408 K range using 780-970 nm tunable wavelengths of 140 fs pulses obtained from a Ti:Sapphire laser at 80 MHz repetition rate. The same pulses were also used for terahertz generation. The linear transmission/absorption properties were measured using a specially improvised temperature-tuned spectrophotometer in the 500-1500 nm wavelength range. The linear absorption of 750 nm wavelength gradually increases with respect to a rise in the temperature, and transmission becomes zero at 408 K. Nonlinear absorption induced by femtosecond pulses shows a sudden drop of 18% in transmission above the 800 nm range, due to electron-phonon interaction, which affects the strength of the terahertz signal. It is also responsible for change in the temperature along with the linear shift in the refractive index of the crystal.
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Agarwal R, Krook NM, Ren ML, Tan LZ, Liu W, Rappe AM, Agarwal R. Anion Exchange in II-VI Semiconducting Nanostructures via Atomic Templating. NANO LETTERS 2018; 18:1620-1627. [PMID: 29406729 DOI: 10.1021/acs.nanolett.7b04424] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Controlled chemical transformation of nanostructures is a promising technique to obtain precisely designed novel materials, which are difficult to synthesize otherwise. We report high-temperature vapor-phase anion-exchange reactions to chemically transform II-VI semiconductor nanostructures (100-300 nm length scale) while retaining the single crystallinity, crystal structure, morphology, and even defect distribution of the parent material via atomic templating. The concept of atomic templating is employed to obtain kinetically controlled, thermodynamically metastable structural phases such as zincblende CdSe and CdS from zincblende CdTe upon complete chemical replacement of Te with Se or S. The underlying transformation mechanisms are explained through first-principles density functional theory calculations. Atomic templating is a unique path to independently tune materials' phase and composition at the nanoscale, allowing the synthesis of novel materials.
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Affiliation(s)
- Rahul Agarwal
- Department of Materials Science and Engineering , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Nadia M Krook
- Department of Materials Science and Engineering , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Ming-Liang Ren
- Department of Materials Science and Engineering , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Liang Z Tan
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
| | - Wenjing Liu
- Department of Materials Science and Engineering , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Andrew M Rappe
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104-6323 , United States
| | - Ritesh Agarwal
- Department of Materials Science and Engineering , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
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Izquierdo E, Robin A, Keuleyan S, Lequeux N, Lhuillier E, Ithurria S. Strongly Confined HgTe 2D Nanoplatelets as Narrow Near-Infrared Emitters. J Am Chem Soc 2016; 138:10496-501. [PMID: 27487074 DOI: 10.1021/jacs.6b04429] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Two-dimensional colloidal nanoplatelets (NPLs), owing to the atomic-level control of their confined direction (i.e., no inhomogeneous broadening), have demonstrated improved photoluminescence (PL) line widths for cadmium chalcogenide-based nanocrystals. Here we use cation exchange to synthesize mercury chalcogenide NPLs. Appropriate control of reaction kinetics enables the 2D morphology of the NPLs to be maintained during the cation exchange. HgTe and HgSe NPLs have significantly improved optical features compared to existing materials with similar band gaps. The PL line width of HgTe NPLs (40 nm full width at half-maximum, centered at 880 nm) is a factor of 2 smaller than typical PbS nanocrystals (NCs) emitting at the same wavelength. The PL has a lifetime of 50 ns, almost 2 orders of magnitude shorter than small PbS colloidal quantum dots (CQDs), and a quantum yield of ∼10%, almost 2 orders of magnitude shorter than small PbS colloidal quantum dots (CQDs). These materials are promising for a large variety of applications spanning from telecommunications to the design of colloidal topological insulators.
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Affiliation(s)
- Eva Izquierdo
- Laboratoire de Physique et d'Étude des Matériaux, PSL Research University, CNRS UMR 8213, ESPCI ParisTech , 10 rue Vauquelin, 75005 Paris, France
| | - Adrien Robin
- Laboratoire de Physique et d'Étude des Matériaux, PSL Research University, CNRS UMR 8213, ESPCI ParisTech , 10 rue Vauquelin, 75005 Paris, France
| | - Sean Keuleyan
- Voxtel, Inc., and CAMCOR 1241, University of Oregon , Eugene, Oregon 97403, United States
| | - Nicolas Lequeux
- Laboratoire de Physique et d'Étude des Matériaux, PSL Research University, CNRS UMR 8213, ESPCI ParisTech , 10 rue Vauquelin, 75005 Paris, France
| | - Emmanuel Lhuillier
- Institut des Nanosciences de Paris, CNRS-UMR 7588, Sorbonne Universités, UPMC Univ Paris 06 , F-75005 Paris, France
| | - Sandrine Ithurria
- Laboratoire de Physique et d'Étude des Matériaux, PSL Research University, CNRS UMR 8213, ESPCI ParisTech , 10 rue Vauquelin, 75005 Paris, France
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Xi L, Hwee Chua K, Zhao Y, Zhang J, Xiong Q, Ming Lam Y. Controlled synthesis of CdE (E = S, Se and Te) nanowires. RSC Adv 2012. [DOI: 10.1039/c2ra20060k] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Mak JSW, Farah AA, Chen F, Helmy AS. Photonic crystal fiber for efficient Raman scattering of CdTe quantum dots in aqueous solution. ACS NANO 2011; 5:3823-3830. [PMID: 21517094 DOI: 10.1021/nn200157z] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A novel hollow-core photonic crystal fiber platform was used for the first time to observe clear vibrational modes of the CdTe core, CdS(0.7)Te(0.3) interface, and carboxylate-metal complexes in dilute aqueous CdTe quantum dot (QD) solutions. These modes demonstrate the presence of crystalline cores, defects, and surface passivation responsible for photoluminescent efficiency and stability. In addition, 3-mercaptopropionic acid (MPA)-capped QDs show higher crystallinity and stability than those capped with thioglycolic acid (TGA) and 1-thioglycerol (TG). This detailed, nondestructive characterization was carried out using Raman spectroscopy for solutions with QD concentration of 2 mg/mL, which is similar to their concentration during synthesis process. This platform can be extended to the in situ studies of any colloidal nanoparticles and aqueous solutions of relevant biological samples using Raman spectroscopy.
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Affiliation(s)
- Jacky S W Mak
- The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario, M5S 3G4 Canada
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Krahne R, Chilla G, Schüller C, Carbone L, Kudera S, Mannarini G, Manna L, Heitmann D, Cingolani R. Confinement effects on optical phonons in polar tetrapod nanocrystals detected by resonant inelastic light scattering. NANO LETTERS 2006; 6:478-82. [PMID: 16522046 DOI: 10.1021/nl0524492] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
We investigated CdTe nanocrystal tetrapods of different sizes by resonant inelastic light scattering at room temperature and under cryogenic conditions. We observe a strongly resonant behavior of the phonon scattering with the excitonic structure of the tetrapods. Under resonant conditions we detect a set of phonon modes that can be understood as confined longitudinal-optical phonons, surface-optical phonons, and transverse-optical phonons in a nanowire picture.
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Affiliation(s)
- Roman Krahne
- National Nanotechnology Laboratory of CNR-INFM c/o Istituto Superiore Universitario di Formazione Interdisciplinare, Università di Lecce, Via per Arnesano, 73100 Lecce, Italy.
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Nakashima SI, Okumura H, Yamamoto T, Shimidzu R. Deep-ultraviolet Raman microspectroscopy: characterization of wide-gap semiconductors. APPLIED SPECTROSCOPY 2004; 58:224-9. [PMID: 17140482 DOI: 10.1366/000370204322842977] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
We have developed a high-throughput deep-ultraviolet (DUV) Raman microspectrometer with excitation from a continuous wave (cw) laser operated at 244 nm that enables us to characterize thin surface layers of wide-gap semiconductors. This spectrometer system consists of a filter spectrometer for the rejection of stray light and a high-dispersion spectrograph combined with a liquid nitrogen cooled charge-coupled device (CCD) detector and extends the low-frequency limit of the observable spectral range down to 170 cm(-1). In the microscope we use a Cassegrain reflective objective for the collection of the scattered light and an off-axis mirror for introduction of the excitation laser light. DUV Raman spectroscopy has been applied for studying wide-gap semiconductors including SiC and AlGaN epitaxial films and shallow implanted layers of these materials. Raman spectra of various crystals have also been measured for examining the performance of this system. Resonance enhancement of Raman bands has been observed for several semiconductors, and the results are discussed.
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Affiliation(s)
- Shin-ichi Nakashima
- National Institute of Advanced Science and Industrial Technology, Central 2, Umezono 1-1-1, Tsukuba, Ibaraki 305-8568 Japan.
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Rath S, Jain KP, Abbi SC, Julien C, Balkanski M. Composition and temperature-induced effects on the phonon spectra of narrow-band-gap Hg1-xCdxTe. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 52:17172-17183. [PMID: 9981144 DOI: 10.1103/physrevb.52.17172] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Artús L, Cuscó R, Martín JM, González-Díaz G. Up to fifth-order Raman scattering of InP under nonresonant conditions. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 50:11552-11555. [PMID: 9975286 DOI: 10.1103/physrevb.50.11552] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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