DOCSLIB.ORG

Solid State Recrystallization of II-VI Semiconductors : Application to Cadmium Telluride, Cadmium Selenide and Zinc Selenide R

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Solid State Recrystallization of II-VI Semiconductors : Application to Cadmium Telluride, Cadmium Selenide and Zinc Selenide R Solid State Recrystallization of II-VI Semiconductors : Application to Cadmium Telluride, Cadmium Selenide and Zinc Selenide R. Triboulet, J. Ndap, A. El Mokri, A. Tromson Carli, A. Zozime To cite this version: R. Triboulet, J. Ndap, A. El Mokri, A. Tromson Carli, A. Zozime. Solid State Recrystallization of II-VI Semiconductors : Application to Cadmium Telluride, Cadmium Selenide and Zinc Selenide. J. Phys. IV, 1995, 05 (C3), pp.C3-141-C3-149. 10.1051/jp4:1995312. jpa-00253678 HAL Id: jpa-00253678 https://hal.archives-ouvertes.fr/jpa-00253678 Submitted on 1 Jan 1995 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. JOURNAL DE PHYSIQUE IV Colloque C3, supplCment au Journal de Physique 111, Volume 5, avril 1995 Solid State Recrystallization of 11-VI Semiconductors: Application to Cadmium Telluride, Cadmium Selenide and Zinc Selenide R. Triboulet, 3.0. Ndap, A. El Mokri, A. Tromson Carli and A. Zozime CNRS, Laboratoire de Physique des Solides de Bellevue, 1 place Aristide Briand, F 92195 Meudon cedex, France Abstract : Solid state recrystallization (SSR) has been very rarely used for semiconductors. It has nevertheless been proposed, and industrially used, for the single crystal growth of cadmium mercury telluride according to a quench-anneal process. The reasons of the interest of this process, in specific cases of 11-VI semiconductors crystal growth, will be analyzed (particular phase diagrams, phase transitions in the solid state close to the melting point, high temperature contaminations..etc.. make the use of traditional melt growth techniques unfavourable) and illustrated refering to CdHgTe literature. Original results related to the binary compounds CdTe, CdSe and ZnSe will be presented. 1. INTRODUCTION Solid state recrystallization (SSR) has been very rarely used for semiconductors, except for cadmium mercury telluride, and more for metals according to a rather different process, generally preceded by plastic deformation. Several reasons can suggest its use for the growth of semiconductors, among which high temperature contamination risks or particular features of the phase diagrams, such as a large merence between liquidus and solidus curves (CdHgTe case), or the existence of phase transitions in the solid state (CdTe and ZnSe cases), or high melting points (CdSe case), making it =cult the use of melt- growth techniques. The cadmium mercury telluride alloys provide a good example of a pseudobinary phase diagram, with a large difference in liquidus and solidus compositions along a given thermal tie line, in which the slow moving interface of a near-equilibrium growth process will invariably result in a steady variation in the composition of the crystal. The features of the HgTe-CdTe phase diagram make it so di£licult the growth of homogeneous crystals that almost all the kinds of growth techniques used for semiconductor materials have been applied to MCT. The QuenchIRecrystallization, or Cast-Recrystallise-Anneal (CRA), process has been the widest used industrially for the single crystal growth of cadmium mercury telluride [l- 41. But even if it is still used now, it has been progressively replaced by the Travelling Heater Method, Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jp4:1995312 C3-142 JOURNAL DE PHYSIQUE IV which has proved to be the only viable MCT bulk growth technique that simultaneously meets the material requirements of large area, uniformity, low defects and well-dehed orientation. Other methods are the epitaxial growth techniques at low temperature, like LPE, MOCVD or MBE. Cadmium telluride and zinc selenide are good examples of iono-covalent semiconductor compounds in which phase transitions in the solid state make the crystals obtained from melt-growth techniques defective. It has been frequently stressed that the bigb ionicity of the chemical bond of some II-VI compounds favors the hexagonal structure. Note that, among the ZI-VI compounds, CdTe and ZnSe present a rather high ionicity, as it can be shown in table 1 in which the ionicities of several 11-VI compounds are gathered together with the structure of their crystalline lattice. table 1 Comuound 1onicitv5 Structure CdS 0.74 Hex. CdSe 0.64 Hex. CdTe 0.55 Cub. twin. ZnS 0.77 Cub.Hex. ZnSe 0.63 Cub.twin. ZnTe 0.49 Cub. HgTe 0.50 Cub. Hex. = hexagonal; cub. = cubic; twin. = twinned The tendency of CdTe to hexagonal structure has been emphasized by several authors, through various experimental investigations. Leibov et al. [6] have reported a phase transition in the 893-920 OC temperature range from a study of thermodynamic properties of CdTe by electromotive forces. The existence of a hexagonal structure at high temperature in CdTe has been also reported by several authors [7-91. Triboulet [lo] has reported a phase transition in the solid state, in the CdTe-MnTe system, between a high temperature hexagonal phase and a low temperature cubic one, with a transition line converging in the vicinity of the melting point of CdTe. This should mean that CdTe could extremely easily oscillate between hexagonal and cubic structures just at its melting point. Ivanov [ll] has reported recently the existence of two phases transitions in the solid state in CdTe at high temperature, at - 980 OC and 900 "C, separating three Werent phases, a,P and y, ftom the high temperature y phase to the "low" temperature a one. Very recently, Rosen [12] has reported also a sharp drop in electric conductivity near 1060°C in CdTe, that could be associated with an allotropic phase transformation, following the statement of Kendall [13] pointing out that electrical properties, such as electric conduct~ty,were closely dependent on the structural symmetry of the substance. All these features could explain why the growth of twin-free CdTe crystals is difEcult fkom the melt. The situation is yet clearer in the ZnSe case. With its high ionicity of 0.63, ZnSe presents a phase transition in the solid state, which has been studied by Kulakov et al. [14]. A reversible phase transition of the first kind has been found at 1425 + 10°C, with a heat of 0.3 kcal mol-l, which was thought to be a transition between the 2H wurtzite form of ZnSe, at high temperature, and the room temperature 3C cubic one. Crossing the transition line during the cooling process induces a very high density of twins, as observed by numerous authors. The existence of phase transitions in the solid state in CdTe and ZnSe justifies the use of low temperature growth, and mainly of SSR as will be seen later. Another sigmiicant example of the interest of SSR for the growth of semiconductor compounds is the case of materials with a melting point higher than the softening temperature of silica, preventing ftom using classical melt-growth techniques. This will be briefly iUustrated in the case of CdSe. Beside the detrimental consequences of high temperature melt-growth, contamination has been also found to occur from the high temperatures used during some growth processes in the case of CdTe [15]. Table 2 displays results of electrical measurements on CdTe crystals grown respectively first by a "low temperature" solution growth technique using Te as the solvent, called "cold THM", in which the material remains at a temperature lower than its melting point over the whole process, second by SSR using such CTHM crystals as source material, and third by vertical Bridgman. Although only 5N elements were used in Cold THM and 6N+ in Bridgman, the purest crystals are the Cold THM ones. The electrical characteristics of the SSR samples show a weak contamination, beside the CTHM ones, as the result of the long annealing process. table 2 Name growth elements N~ N A N~/N~p300~ pmax E~ method Tgrowth (cm-3) (cm-3) cm2Ns cm2Ns meV CTH59 CTHM 5NTe, 6NCd 3.4~1014 1.5x1013 0.04 840 41,400 14 TG = 780°C (28K) CTRE SSR 5N Te, 6N Cd 7.6~1014 2.2~10~~0.03 780 9,000 11.2 TG = 990°C (22K) CT64 Bridgman 6N+CdandTe 2.6x1015 1.6x1015 0.7 800 12,500 9 TG = 1100°C (36K) 2. WHAT "LOW TEMPERATURE" CRYSTAL GROWTH TECHNIQUE TO BE USED ? All the previous considerations justify the use of low temperature growth, for which several techniques can compete, among which solution growth, vapour phase growth and solid state recrystallization. C3-144 JOURNAL DE PHYSIQUE IV In the case of the growth of CdTe and CdZnTe by THM, which has been the most popular solution growth method during the last decade, the crystallographic properties of the crystals suffer from their large stoichiometric deviation, arising from the Te-rich growth conditions. Some mosalc structure is found as the result of these growth conditions, as shown for instance by the multipeak spectra of the rocking-curves measured in X-ray double *action [15]. Moreover, the Te-rich growth conditions together with the retrograde shape of the solidus line lead also to the unavoidable presence of Te precipitates that are detrimental to the use of the crystals as substrate. In the ZnSe case, due to the low ZnSe solubility in both Zn and Se, it has been shown necessary to have recourse to heterosolvent growth [16]. But the solvent used, either In or PbC12, gives rise to residual precipitates in the crystals.
Load more

Recommended publications
  • Zinc Selenide Quantum Dots
    Chapter 3 Zinc Selenide Quantum Dots 3.1 Introduction: Nanoscale materials have been extensively studied in recent years to study the evolution of the electronic structure from molecules to bulk. The properties or the electronic structure of nanoparticles is not a simple extrapolation of its corresponding molecular or bulk state. Quantum dots show unique features arising from the variation in crystal structure parameters, discretization of electron energy levels, concentration of oscillator strength for particular transitions, high polarizability of electron energy levels and increased surface to volume ratio [1-4]. Quantum confinement in semiconductors leads to discrete transitions that are blue shifted in energy from the bulk. Inhomogeneous broadening of the optical spectra due to size distribution and shape variations of the nanoparticles, conceal the fine structure in the energy states of quantum dots. In order to study the evolution of the electronic, optical and structural properties of material with size it is essential to synthesize nanoparticles of different sizes (with narrow size distribution) and controlled surface properties. II-VI semiconductors are relatively easy to synthesize, yielding free standing colloidal quantum dots by wet chemical routes. The evolving electronic structure as a function of size can be determined by non-contact optical probes in case of direct band gap II-VI semiconductors. The quantum size effects in CdSe nanoparticles with wurtzite structure are thoroughly investigated [5], while relatively less attention is being paid to other II-VI nanocrystals such as zinc selenide or zinc oxide. ZnSe is a II-VI direct band gap, zinc blende semiconductor with a bulk band gap of 2.7 eV at room temperature.
    [Show full text]
  • Selenium Nutritional, Toxicologic, and Clinical Aspects ANNA M
    160 Articles Selenium Nutritional, Toxicologic, and Clinical Aspects ANNA M. FAN, PhD, Berkeley, and KENNETH W. KIZER, MD, MPH, Sacramento, California This is one ofa series ofarticles from western state public health departments. Despite the recent findings ofenvironmental contamination, selenium toxicosis in humans is exceedingly rare in the United States, with the few known cases resulting from industrial accidents and an episode involving the ingestion of superpotent selenium supplements. Chronic selenosis is essentially unheard of in this country because of the typical diversity of the American diet. Nonetheless, because ofthe growing public interest in selenium as a dietary supplement and the occurrence ofenvironmental selenium contamination, medical practitioners should be familiar with the nutritional, toxicologic, and clinical aspects of this trace element. (Fan AM, Kizer KW: Selenium-Nutritional, toxicologic, and clinical aspects. West J Med 1990 Aug; 153:160-167) Since the recognition of the nutritional essentiality of and other parts of the world.4 Highly seleniferous soils selenium (Se) in animals in 1957, there has been ever- yielding selenium-toxic plants (such as Astragalus bisulca- increasing interest in this trace element. This interest has tus) are widespread in South Dakota, Wyoming, Montana, heightened in the past decade concomitant with the recog- North Dakota, Nebraska, Kansas, Colorado, Utah, Arizona, nition of selenium's essential nutritional role in humans and New Mexico. Soil containing high selenium concentra- and reports of selenium toxicity among humans. Interest in tions but not yielding toxic plants is found in Hawaii. selenium has been further aroused recently by the findings of elevated levels of this compound in certain soils and wa- Chemical Forms ter sources in the western United States, leading to adverse Selenium is a nonmetallic element chemically related to effects on fish and wildlife (T.
    [Show full text]
  • The Electronic and Optical Properties of Close Packed Cadmium Selenide Quantum Dot Solids
    The Electronic and Optical Properties of Close Packed Cadmium Selenide Quantum Dot Solids by Cherie Renee Kagan B. S. E. Materials Science and Engineering B. A. Mathematics University of Pennsylvania, Philadelphia, PA 1991 Submitted to the Department of Materials Science and Engineering in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY September 1996 0 1996 Massachusetts Institute of Technology All rights reserved Signature of the Author Departmenf of Materials Science and Engineering August 9, 1996 Certified by_ Moungi G. Bawendi Professor of Chemistry Thesis Supervisor Accepted by Linn W. Hobbs John F. Elliott Professor of Materials Science and Engineering Chair, Department Committee on Graduate Students AROHIvES ()F Tac(.!-otodY SEP 2 71996 Room 14-0551 77 Massachusetts Avenue Cambridge, MA 02139 Ph: 617.253.2800 MITLbries Email: [email protected] Document Services http://Iibraries.mit.eduldocs DISCLAIMER OF QUALITY Due to the condition of the original material, there are unavoidable flaws in this reproduction. We have made every effort possible to provide you with the best copy available. If you are dissatisfied with this product and find it unusable, please contact Document Services as soon as possible. Thank you. The images contained in this document are of the best quality available. 2 3 The Electronic and Optical Properties of Close Packed Cadmium Selenide Quantum Dot Solids by Cherie Renee Kagan - Submitted to the Department of Materials Science and Engineering on August 9, 1996 in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in Materials Science and Engineering Abstract The synthesis, structural characterization, optical spectroscopy, and electronic characterization of close packed solids prepared from CdSe QD samples tunable in size from 17 to 150 A in diameter (a<4.5%) are presented.
    [Show full text]
  • Zinc Selenide Optical Crystal
    Revision date: 07/12/2020 Revision: 1 SAFETY DATA SHEET Zinc Selenide Optical Crystal SECTION 1: Identification of the substance/mixture and of the company/undertaking 1.1. Product identifier Product name Zinc Selenide Optical Crystal CAS number 1315-09-9 EU index number 034-002-00-8 EC number 215-259-7 1.2. Relevant identified uses of the substance or mixture and uses advised against Identified uses Optical Material for manufacture of Optical Components 1.3. Details of the supplier of the safety data sheet Supplier Knight Optical (UK) LTD Roebuck Business Park Harrietsham Kent ME17 1AB UK +44 (0)1622 859444 [email protected] 1.4. Emergency telephone number Emergency telephone +44 (0)1622 859444 (Monday to Friday 08:30 to 17:00 GMT) SECTION 2: Hazards identification 2.1. Classification of the substance or mixture Classification (EC 1272/2008) Physical hazards Not Classified Health hazards Acute Tox. 3 - H301 Acute Tox. 3 - H331 Environmental hazards Aquatic Chronic 1 - H410 2.2. Label elements EC number 215-259-7 Hazard pictograms Signal word Danger Hazard statements H301+H331 Toxic if swallowed or if inhaled. H410 Very toxic to aquatic life with long lasting effects. 1/10 Revision date: 07/12/2020 Revision: 1 Zinc Selenide Optical Crystal Precautionary statements P264 Wash contaminated skin thoroughly after handling. P270 Do not eat, drink or smoke when using this product. P273 Avoid release to the environment. P403+P233 Store in a well-ventilated place. Keep container tightly closed. P501 Dispose of contents/ container in accordance with national regulations.
    [Show full text]
  • Journal of Materials Chemistry C Rscpublishing COMMUNICATION
    Journal of Materials Chemistry C RSCPublishing COMMUNICATION The room temperature phosphine-free organometallic synthesis of near-infrared emitting Cite this: DOI: 10.1039/x0xx00000x HgSe quantum dots H. Mirzai,a M. N. Nordin,b,c R. J. Curry,b J.-S. Bouillard,a A. V. Zayats,a M. a Received 00th January 2012, Green* Accepted 00th January 2012 DOI: 10.1039/x0xx00000x Luminescent mercury selenide (HgSe) quantum dots have been synthesised by a phosphine- free method using oleic acid as a capping agent. The modification of experimental conditions www.rsc.org/ such as temperature resulted in particles of various sizes (15 - 100 nm) and morphologies not previously seen in HgSe, with emission tuneable between 1000 nm and 1350 nm. The popularity of semiconductor quantum dots (QDs) and b Advanced Technology Institute, Department of Electronic Engineering, their association with next-generation opto-electronic devices University of Surrey, Guildford, Surrey.UK GU2 7XH c and biomedical applications has grown rapidly over the last Present address: Medical Engineering Technology Department, University Kuala Lumpur, 53100, Gombak, Malaysia. years. Current research focuses on various synthetic routes as a means to modify QD characteristics to satisfy specific due to the lack of obvious and safe precursors (despite the optical and magnetic requirements for applications such as fact that many early routes to nano-dispersed semiconductors biological imaging,1 telecommunications,2 photodetection3 4 were based on mercury chalcogenides). We have focused on and solar energy. Quantum dots have provided a new source mercury chalcogenides due to their low reaction temperatures of electromagnetic radiation on the nano-scale.
    [Show full text]
  • Table of Contents (Print, Part 1)
    CONTENTS - Continued PHYSICAL REVIEW B THIRD SERIES, VOLUME 90, NUMBER 16 OCTOBER 2014-15(II) COMMENTS Comment on “Canonical magnetic insulators with isotropic magnetoelectric coupling” (3 pages) ............... 167101 J. M. Perez-Mato, Samuel V. Gallego, E. S. Tasci, L. Elcoro, and M. I. Aroyo Reply to “Comment on ‘Canonical magnetic insulators with isotropic magnetoelectric coupling’ ” (1 page) . 167102 Sinisa Coh and David Vanderbilt Comment on “Ideal strength and phonon instability in single-layer MoS2” (3 pages) .......................... 167401 Ryan C. Cooper, Jeffrey W. Kysar, and Chris A. Marianetti Reply to “Comment on ‘Ideal strength and phonon instability in single-layer MoS2’”(3 pages) ................ 167402 Tianshu Li The editors and referees of PRB find these papers to be of particular interest, importance, or clarity. Please see our Announcement Phys. Rev. B 77, 130001 (2008). CONTENTS - Continued PHYSICAL REVIEW B THIRD SERIES, VOLUME 90, NUMBER 16 OCTOBER 2014-15(II) Readout and dynamics of a qubit built on three quantum dots (12 pages) .................................... 165427 Jakub Łuczak and Bogdan R. Bułka Experimental verification of reciprocity relations in quantum thermoelectric transport (6 pages) ................ 165428 J. Matthews, F. Battista, D. Sanchez,´ P. Samuelsson, and H. Linke Noncollinear magnetic phases and edge states in graphene quantum Hall bars (5 pages) ....................... 165429 J. L. Lado and J. Fernandez-Rossier´ Roton-maxon spectrum and instability for weakly interacting dipolar excitons in a semiconductor layer (9 pages) 165430 A. K. Fedorov, I. L. Kurbakov, and Yu. E. Lozovik Influence of edge and field effects on topological states of germanene nanoribbons from self-consistent calculations (7 pages) ................................................................................ 165431 Lars Matthes and Friedhelm Bechstedt Electronic structure and magnetic properties of cobalt intercalated in graphene on Ir(111) (10 pages) ..........
    [Show full text]
  • Properties of Sputtered Mercury Telluride Contacts on P-Type Cadmium Telluride A
    Properties of sputtered mercury telluride contacts on p-type cadmium telluride A. Zozime, C. Vermeulin To cite this version: A. Zozime, C. Vermeulin. Properties of sputtered mercury telluride contacts on p-type cadmium telluride. Revue de Physique Appliquée, Société française de physique / EDP, 1988, 23 (11), pp.1825- 1835. 10.1051/rphysap:0198800230110182500. jpa-00246011 HAL Id: jpa-00246011 https://hal.archives-ouvertes.fr/jpa-00246011 Submitted on 1 Jan 1988 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Revue Phys. Appl. 23 (1988) 1825-1835 NOVEMBRE 1988, 1825 Classification Physics Abstracts 73.40 - 79.20 Properties of sputtered mercury telluride contacts on p-type cadmium telluride A. Zozime and C. Vermeulin Laboratoire de Physique des Matériaux, CNRS, 1 place A. Briand, 92195 Meudon Cedex, France (Reçu le 12 avril 1988, révisé le 29 juillet 1988, accepté le 16 août 1988) Résumé. 2014 La valeur élevée du travail de sortie du composé semi-métallique HgTe (q03A6m ~ 5.9 eV) a conduit à utiliser ce matériau pour réaliser des contacts ohmiques de faible résistance spécifique 03C1c (03A9 cm2) sur le composé semi-conducteur II-VI CdTe de type p, dans la gamme des résistivités 70 03A9 cm 03C1B 45 k03A9 cm.
    [Show full text]
  • Trends in Performance Limits of the HOT Infrared Photodetectors
    applied sciences Review Trends in Performance Limits of the HOT Infrared Photodetectors Antoni Rogalski 1, Piotr Martyniuk 1,*, Małgorzata Kopytko 1 and Weida Hu 2 1 Faculty of Advanced Technologies and Chemistry, Institute of Applied Physics, Military University of Technology, 2 Kaliskiego St., 00-908 Warsaw, Poland; [email protected] (A.R.); [email protected] (M.K.) 2 State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 500 Yu Tian Road, Shanghai 200083, China; [email protected] * Correspondence: [email protected]; Tel.: +48-26-183-92-15 Abstract: The cryogenic cooling of infrared (IR) photon detectors optimized for the mid- (MWIR, 3–5 µm) and long wavelength (LWIR, 8–14 µm) range is required to reach high performance. This is a major obstacle for more extensive use of IR technology. Focal plane arrays (FPAs) based on thermal detectors are presently used in staring thermal imagers operating at room temperature. However, their performance is modest; thermal detectors exhibit slow response, and the multispectral detection is difficult to reach. Initial efforts to develop high operating temperature (HOT) photodetectors were focused on HgCdTe photoconductors and photoelectromagnetic detectors. The technological efforts have been lately directed on advanced heterojunction photovoltaic HgCdTe detectors. This paper presents the several approaches to increase the photon-detectors room-temperature performance. Various kinds of materials are considered: HgCdTe, type-II AIIIBV superlattices, two-dimensional materials and colloidal quantum dots. Keywords: HOT IR detectors; HgCdTe; P-i-N; BLIP condition; 2D material photodetectors; colloidal quantum dot photodetectors Citation: Rogalski, A.; Martyniuk, P.; Kopytko, M.; Hu, W.
    [Show full text]
  • Material Safety Data Sheet
    LTS Research Laboratories, Inc. Safety Data Sheet Zinc Selenide ––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– 1. Product and Company Identification ––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– Trade Name: Zinc selenide Chemical Formula: ZnSe Recommended Use: Scientific research and development Manufacturer/Supplier: LTS Research Laboratories, Inc. Street: 37 Ramland Road City: Orangeburg State: New York Zip Code: 10962 Country: USA Tel #: 855-587-2436 / 855-lts-chem 24-Hour Emergency Contact: 800-424-9300 (US & Canada) +1-703-527-3887 (International) ––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– 2. Hazards Identification ––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– Signal Word: Danger Hazard Statements: H301+H331: Toxic if swallowed or if inhaled H373: May cause damage to organs through central nervous system, the liver, and the digestive system through prolonged or repeated exposure. Route of exposure: Oral, inhalative. H410 Very toxic to aquatic life with long lasting effects Precautionary Statements: P260 Do not breathe dust/fume/gas/mist/vapours/spray P264 Wash skin thoroughly after handling P273: Avoid release to the environment P270: Do not eat, drink, or smoke when using this product. P309: IF exposed or you feel unwell: P310: Immediately call a POISON CENTER or doctor/physician P302+P352: IF ON SKIN: Wash with soap and water P391: Collect
    [Show full text]
  • Investigations of Phonons in Zinc Blende and Wurtzite by Raman Spectroscopy 25
    ProvisionalChapter chapter 2 Investigations of of Phonons Phonons in Zinc in Zinc Blende Blende and Wurtziteand Wurtzite by Raman Spectroscopy by Raman Spectroscopy Lin Sun, Lingcong Shi and Chunrui Wang Lin Sun, Lingcong Shi and Chunrui Wang Additional information is available at the end of the chapter Additional information is available at the end of the chapter http://dx.doi.org/10.5772/64194 Abstract The importance of phonons and their interactions in bulk materials is well known to those working in the fields of solid‐state physics, solid‐state electronics, optoelectronics, heat transport, quantum electronic, and superconductivity. Phonons in nanostructures may act as a guide to research on dimensionally confined phonons and lead to phonon effects in nanostructures and phonon engineering. In this chapter, we introduce phonons in zinc blende and wurtzite nanocrystals. First, the basic structure of zinc blende and wurtzite is described. Then, phase transformation between zinc blende and wurtzite is presented. The linear chain model of a one‐dimensional diatomic crystal and macroscopic models are also discussed. Basic properties of phonons in wurtzite structure will be considered as well as Raman mode in zinc blende and wurtzite structure. Finally, phonons in ZnSe, Ge, SnS2, MoS2, and Cu2ZnSnS4 nanocrystals are discussed on the basis of the above theory. Keywords: phonons, zinc blende, wurtzite, Raman spectroscopy, molecular vibration 1. Zinc blende and wurtzite structure Crystals with cubic/hexagonal structure are of major importance in the fields of electronics and optoelectronics. Zinc blende is typical face‐centered cubic structure, such as Si, Ge, GaAs, and ZnSe. Wurtzite is typical hexagonal close packed structure, such as GaN and ZnSe.
    [Show full text]
  • Bandgap-Engineered Hgcdte Infrared Detector Structures for Reduced Cooling Requirements
    Bandgap-Engineered HgCdTe Infrared Detector Structures for Reduced Cooling Requirements by Anne M. Itsuno A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Electrical Engineering) in The University of Michigan 2012 Doctoral Committee: Associate Professor Jamie D. Phillips, Chair Professor Pallab K. Bhattacharya Professor Fred L. Terry, Jr. Assistant Professor Kevin P. Pipe c Anne M. Itsuno 2012 All Rights Reserved To my parents. ii ACKNOWLEDGEMENTS First and foremost, I would like to thank my research advisor, Professor Jamie Phillips, for all of his guidance, support, and mentorship throughout my career as a graduate student at the University of Michigan. I am very fortunate to have had the opportunity to work alongside him. I sincerely appreciate all of the time he has taken to meet with me to discuss and review my research work. He is always very thoughtful and respectful of his students, treating us as peers and valuing our opinions. Professor Phillips has been a wonderful inspiration to me. I have learned so much from him, and I believe he truly exemplifies the highest standard of teacher and technical leader. I would also like to acknowledge the past and present members of the Phillips Research Group for their help, useful discussions, and camaraderie. In particular, I would like to thank Dr. Emine Cagin for her constant encouragement and humor. Emine has been a wonderful role model. I truly admire her expertise, her accom- plishments, and her unfailing optimism and can only hope to follow in her footsteps. I would also like to thank Dr.
    [Show full text]
  • Synthesis, Characterization and Optical Properties of Znse Nanoparticles
    International Journal of Applied Engineering Research ISSN 0973-4562 Volume 13, Number 6 (2018) pp. 4606-4609 © Research India Publications. http://www.ripublication.com Synthesis, Characterization and Optical Properties of ZnSe Nanoparticles Anil Yadav1, 2*, S. P. Nehra2, Dinesh Patidar3 1Department of Chemical Engineering, Deenbandhu Chhotu Ram University of Science & Technology, Murthal, Sonepat (Haryana) India. 2Centre of Excellence for Energy & Environmental Studies, Deenbandhu Chhotu Ram University of Science & Technology, Murthal, Sonepat (Haryana) India. 3Department of Physics, Seth G.B. Podar College, Nawalgarh, Jhunjhunu (Rajasthan) India. *Corresponding Author Abstract characterization of ZnSe semiconductors consisting particles of 2-100 nm, which are generally referred as quantum dots The chemical co-precipitation method was employed to and nanocrystals. The interests of the researchers are mainly synthesize zinc selenide (ZnSe ) nanoparticles with the help of because of their size-tunable optical, electronic and chemical Selenium powder, sodium borohydride, zinc acetate. properties [3,4]. Further miniaturization of optical and Mercaptoethanol was added as capping agent. The XRD, electronic devices leads to their commercial applications [1,4- SEM and TEM techniques were employed for the 9] are as diverse as solar cells, catalysis, biological labelling, characterization of ZnSe nanoparticles. The average diameter light-emitting diodes. As we know that Size and shape of the of ZnSe nanoparticles is 15 nm. HR transmission electron nanomaterials are responsible for their properties but synthesis microscopy (HRTEM) image displays the crystalline features of stable monodispersed nanocrystals is still a great challenge of ZnSe nanoparticles. The PL emission spectrum indicates a in Nanoscience. The control of shape of nanocrystals is also peak centered at 480 nm along with two shoulders at 453 and very important .The correlation exists between the shape and 520 nm.
    [Show full text]