Preparation and Characterisation of (ZnTe)x(CdSe)1−x Single Crystals

MRS Proceedings ◽

10.1557/proc-161-51 ◽

1989 ◽

Vol 161 ◽

Author(s):

V.K. Madhu Smitha Rani ◽

R.P. Vijayalakshmi ◽

D. Raja Reddy ◽

B.K. Reddy

Keyword(s):

Chemical Analysis ◽

Single Crystals ◽

Entire Range ◽

Energy Gap ◽

Spectral Response ◽

Alloy System ◽

Crystalline Form ◽

Reflection Spectra ◽

Alloy Material ◽

P Type

ABSTRACTThe titlematerial is one of the least studied among the II-VI alloy systems. So far it has not been possible to prepare ZnTe in n-type and CdSe in p-type with appreciable conductivities. Moreover ZnTe crystallises in zincblende whereas CdSe crystallises in wurtzite structure. Because of the varied nature of the end compounds, an attempt has been made to prepare single crystals of (ZnTe)x(CdSe)1−x in the entire range of ‘x’. The alloy material in the entire range Xof composition in the single crystalline form was grown by a modified Piper-Plich method. The grown crystals of this alloy system have been subjected to chemical analysis. DTA and DTG studies carried out on these alloys did not show any phasec transitions. However two exothermic peaks associated with increase in mass were noticed. This has been attributed to oxidation effects of Se/Te or Cd/Zn. XRD data though showed some regularity near end compositions there is still some ambiguity for the middle compositions. Energy gap obtained from reflection spectra and also photocurrent spectral response showed bowing. However, there is a marked different feature at one of the end regions. The growth and the results of all the above mentioned investigations are presented and discussed in this paper.

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Electrical Transport Properties of the Pentatelluride Materials Hfte5 and Zrte5

MRS Proceedings ◽

10.1557/proc-478-249 ◽

1997 ◽

Vol 478 ◽

Cited By ~ 6

Author(s):

T. M. Tritt ◽

M. L. Wilson ◽

R. L. Littleton ◽

C. Feger ◽

J. Kolis ◽

...

Keyword(s):

Single Crystal ◽

Single Crystals ◽

Electrical Transport ◽

Entire Range ◽

Room Temperature ◽

Polycrystalline Material ◽

Polycrystalline Materials ◽

Electrical Transport Properties ◽

Low Dimensional ◽

P Type

AbstractWe have measured the resistivity and thermopower of single crystals as well as polycrystalline pressed powders of the low-dimensional pentatelluride materials: HfTe5 and ZrTe5. We have performed these measurements as a function of temperature between 5K and 320K. In the single crystals there is a peak in the resistivity for both materials at a peak temperature, Tp where Tp ≈ 80K for HfTe5 and Tp ≈ 145K for ZrTe5. Both materials exhibit a large p-type thermopower around room temperature which undergoes a change to n-type below the peak. This data is similar to behavior observed previously in these materials. We have also synthesized pressed powders of polycrystalline pentatelluride materials, HfTe5 and ZrTe5. We have measured the resistivity and thermopower of these polycrystalline materials as a function of temperature between 5K and 320K. For the polycrystalline material, the room temperature thermopower for each of these materials is relatively high, +95 μV/K and +65 μV/K for HfTe5 and ZrTe5 respectively. These values compare closely to thermopower values for single crystals of these materials. At 77 K, the thermopower is +55 μV/K for HfTe5 and +35 μV/K for ZrTe5. In fact, the thermopower for the polycrystals decreases monotonically with temperature to T ≈ 5K, thus exhibiting p-type behavior over the entire range of temperature. As expected, the resistivity for the polycrystals is higher than the single crystal material, with values of 430 mΩ-cm and 24 mΩ-cm for Hfre5 and ZrTe5 respectively, compared to single crystal values of 0.35 mΩ-cm (HfTe5) and 1.0 mΩ-cm (ZrTe5). We have found that the peak in the resistivity evident in both single crystal materials is absent in these polycrystalline materials. We will discuss these materials in relation to their potential as candidates for thermoelectric applications.

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Growth of Antimony Selenide Crystals by Bridgman-Stockbarger Method

Mapana Journal of Sciences ◽

10.12723/mjs.15.1 ◽

2009 ◽

Vol 8 (2) ◽

pp. 1-6

Author(s):

Chandrasekharan K. A. ◽

Kunjomana A. G.

Keyword(s):

Chemical Analysis ◽

Diffraction Analysis ◽

Single Crystals ◽

Powder Diffraction ◽

Vickers Hardness ◽

Energy Gap ◽

X Ray ◽

Hardness Tester ◽

Stockbarger Method ◽

Antimony Selenide

Single crystals of antimony selenide were grown from melt by the Bridgman Stockbarger method. X-ray powder diffraction analysis was carried out to determine the lattice parameters of the grown samples.The morphology and chemical analysis of cleavage planes were investigated using SEM and EDAX. The microhardness studies were done by using a Vickers hardness tester. The correlation of energy gap and microhardness has also been investigated.

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Tuning the π–π overlap and charge transport in single crystals of an organic semiconductor via solvation and polymorphism

Physical Chemistry Chemical Physics ◽

10.1039/d0cp03109g ◽

2020 ◽

Vol 22 (35) ◽

pp. 19855-19863

Author(s):

Marc Courté ◽

Jun Ye ◽

Hui Jiang ◽

Rakesh Ganguly ◽

Shasha Tang ◽

...

Keyword(s):

Charge Transport ◽

Transport Properties ◽

Single Crystals ◽

Organic Semiconductors ◽

Organic Semiconductor ◽

Crystalline Form ◽

Organic P ◽

Single Crystalline ◽

Type Semiconductor ◽

P Type

We report here on the occurrence of two solvates and three polymorphs in single crystalline form of an organic p-type semiconductor and demonstrate here that solvation allows to tune the π–π overlap and transport properties of organic semiconductors.

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Features of IR reflection spectra of β-Tl1-xCuxInS2 single crystals (0 ≤ X ≤ 0.015)

Journal of Physics Conference Series ◽

10.1088/1742-6596/1753/1/012077 ◽

2021 ◽

Vol 1753 (1) ◽

pp. 012077

Author(s):

A Kh Matiyev ◽

R T Uspazhiev ◽

A M Gachaev ◽

I A Sysoev ◽

B M Khamkhoev ◽

...

Keyword(s):

Single Crystals ◽

Reflection Spectra ◽

Ir Reflection ◽

Ir Reflection Spectra

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A High Seebeck Voltage Thermoelectric Module with P‐type and N‐type MAPbI 3 Perovskite Single Crystals

Advanced Electronic Materials ◽

10.1002/aelm.202001003 ◽

2021 ◽

pp. 2001003

Author(s):

Zuoxiang Xie ◽

Kai Feng ◽

Yan Xiong ◽

Xu Chen ◽

Yudong Liang ◽

...

Keyword(s):

Single Crystals ◽

Thermoelectric Module ◽

P Type ◽

Seebeck Voltage

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CdSe/CdS Quantum Dot Core-Shell for Silicon Solar Cell Efficiency Enhancement

Nano Hybrids and Composites ◽

10.4028/www.scientific.net/nhc.29.8 ◽

2020 ◽

Vol 29 ◽

pp. 8-14

Author(s):

Manal Midhat Abdullah ◽

Omar Adnan Ibrahim

Keyword(s):

Solar Cell ◽

Silicon Solar Cell ◽

Energy Gap ◽

Spectral Response ◽

Solar Spectrum ◽

Core Shell ◽

Solar Cell Efficiency ◽

Cell Efficiency ◽

Electron Hole Pair ◽

Pair Generation

Core-shell nanocrystals are utilized to improve vitality conversion efficiency of Si based solar cells. In the present work, a study of synthesis and characterization of photo luminescent, down-shifting, core-shell CdSe/CdS quantum dots is introduced. The QD,s absorb in the UV range (350nm) of the solar spectrum and emit photons with wavelengths centered at (574 nm). Calculated energy gap is (2.16 eV), which is well suited for Silicon absorption and electron-hole pair generation. The grain size is ranged between (1.814 and 3.456 nm). Results show that the cell efficiency is improved from (8.81%) (For a reference silicon solar cell) to (10.07%) (For a CdSe/CdS QD deposited directly on the surface of the solar cell). This improvement is referred to the spreading of the absorbed solar radiation over the spectral response of the Si solar cell.

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Isotopic disorder effect in the infrared reflection spectra of 6Lix7Li1−xY F4 single crystals

Solid State Communications ◽

10.1016/j.ssc.2007.02.032 ◽

2007 ◽

Vol 142 (5) ◽

pp. 256-260

Author(s):

E.A. Vinogradov ◽

V.A. Yakovlev ◽

N.N. Novikova ◽

M.N. Popova ◽

S.K. Saikin ◽

...

Keyword(s):

Single Crystals ◽

Reflection Spectra ◽

Infrared Reflection ◽

Disorder Effect

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Fabrication of Bi-Te Based Thermoelectric Semiconductors by Using Hybrid Powders

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.297-300.875 ◽

2005 ◽

Vol 297-300 ◽

pp. 875-880

Author(s):

Cheol Ho Lim ◽

Ki Tae Kim ◽

Yong Hwan Kim ◽

Dong Choul Cho ◽

Young Sup Lee ◽

...

Keyword(s):

Mechanical Properties ◽

Single Crystals ◽

Thermoelectric Properties ◽

Thermoelectric Materials ◽

Figure Of Merit ◽

Bending Strength ◽

Mixing Ratio ◽

Plasma Sintering ◽

Spark Plasma ◽

P Type

P-type Bi0.5Sb1.5Te3 compounds doped with 3wt% Te were fabricated by spark plasma sintering and their mechanical and thermoelectric properties were investigated. The sintered compounds with the bending strength of more than 50MPa and the figure-of-merit 2.9×10-3/K were obtained by controlling the mixing ratio of large powders (PL) and small powders (PS). Compared with the conventionally prepared single crystal thermoelectric materials, the bending strength was increased up to more than three times and the figure-of-merit Z was similar those of single crystals. It is expected that the mechanical properties could be improved by using hybrid powders without degradation of thermoelectric properties.

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