Growth and characterizations of bulk ZnSe single crystal by chemical vapor transport (original) (raw)
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Studies on structural and optical properties of ZnSe and ZnSSe single crystals grown by CVT method
Journal of Crystal Growth, 2014
The ZnSe and ZnSSe single crystals have been grown by chemical vapour transport (CVT) with iodine as a transporting agent. The source and growth temperatures of the reactor are maintained at 850 1C and 900 1C respectively using the two zone horizontal resistive heating furnace. The grown crystals are characterised by structural, surface morphological and optical properties. The XRD pattern shows that the peaks due to reflection from (111), (220) and (311) planes belong to the cubic zinc-blend structure. The composition of grown ZnSe crystal has been determined by EDXRF analysis as Zn (52.5%) and Se (47.5%). The XPS study of grown ZnSe single crystal has been studied. The HRSEM images reveal the step, spiral and triangular patterns. The optical absorption study reveals the absorption cut off wavelength as 483 nm (2.57 eV) for ZnSe and 441 nm (2.81 eV) for ZnSSe crystals. The photoluminescence studies reveal the band edge emission and defect level emissions of ZnSe and ZnSSe single crystals.
Nonstoichiometry and luminescent properties of ZnSe crystals grown from melt and vapor
Journal of Crystal Growth, 2014
ZnSe homogeneity region was studied by direct physico-chemical method in 730-1320 K temperature range. It was established that the homogeneity region included stoichiometric composition and solidus lines both from Zn-and Se-rich sides demonstrated the retrograde behavior. Comparison of ZnSe nonstoichiometry with ionized defect concentrations at S ZnSe-L (Zn)-V equilibrium had let us assert that at the examined conditions the dominant point defects are electrically neutral. Nonstoichiometry analysis of ZnSe crystals grown from melt under high pressure and from vapor by the Markov-Davydov technique showed that there were Se-excess over stoichiometry in melt grown ZnSe and Zn-excess close to stoichiometry in vapor grown crystals.
Applied Surface Science, 2006
The zinc selenide thin films have been deposited using modified chemical bath deposition (M-CBD) method. Zinc acetate and sodium selenosulphate were used as Zn 2+ and Se 2À ion sources, respectively. The preparative parameters such as concentration, pH, number of deposition cycles have been optimized in order to deposit ZnSe thin films. The as-deposited ZnSe thin films are specularly reflective and faint yellowish in color. The as-deposited ZnSe films are annealed in an air atmosphere at 473 K for 2 h. The films are characterized using structural, morphological, compositional, optical and electrical properties.
Characterization of single crystalline ZnTe and ZnSe grown by vapor phase transport
Journal of Physics: Conference Series, 2009
Tubular furnaces were designed and built to obtain single crystalline ZnTe and ZnSe ingots using respectively physical and chemical transport methods. Different temperature profiles and growth rates were analyzed in order to optimize the necessary crystalline quality for device development. Optical and scanning electron micrographs of the corrosion figures produced by chemical etching were used to obtain the dislocation density and the misorientation between adjacent subgrains in ZnTe and ZnSe wafers. Structural quality of the single crystalline material was determined by transmission electronic microscopy. Optical transmittance was measured by infrared transmission spectrometry and the resulting values were compared to commercial samples.
Comparative Study of Bulk and Nanoengineered Doped ZnSe
Crystals, 2022
Chromium- and cobalt-doped zinc selenide nanoparticles were synthesized using a low-temperature reactive solution growth method. The morphological and optical characteristics were compared to those of doped zinc selenide (ZnSe) bulk crystals grown by the physical vapor transport (PVT) method. We observed agglomeration of particles; however, the thioglycerol capping agent has been shown to limit particle grain growth and agglomeration. This process enables doping by addition of chromium and cobalt salts in the solution. A slightly longer refluxing time was required to achieve cobalt doping as compared with chromium doping due to lower refluxing temperature. The nanoparticle growth process showed an average particle size of approximately 300 nm for both Cr- and Co-doped zinc selenide. The optical characterization of Co:ZnSe is ongoing; however, preliminary results showed a very high bandgap compared to that of pure ZnSe bulk crystal. Additionally, Co:ZnSe has an order of magnitude hig...
STUDY ON NANOPARTICLES OF ZnSe SYNTHESIZED BY CHEMICAL METHOD AND THEIR CHARACTERIZATION
2011
The properties of semiconductor nanoparticles depend mainly on their shape and size due to high surface-to-volume ratio. The II-VI semiconductors have many applications such as, LED, acousto-optical effects and biological sensors. The ZnSe nanoparticles have wide-ranging applications in laser, optical instruments etc. because it has wide band gap and transmittance range, high luminescence efficiency, low absorption coefficient. In recent years, much attention was paid on the preparation methods, performances and applications of ZnSe nanoparticles and thin solid films, and a lot of important accomplishments have been obtained. In the present study ZnSe nanoparticles were successfully prepared by reacting Zn(CH 3 COO) 2 2H 2 O and Na 2 SeSO 3 at 343 K. The size of the crystallite was estimated by X-ray diffraction and TEM, whereas EDAX has confirmed of no foreign impurity inclusion in ZnSe nanoparticles. XRD shows the crystallite size of 5.68 n m a n d T E M g i v e s a distribution ranging from 20 nm to 71 nm. A SEM image shows that the particles are spherical in a shape. Quantum confinement has resulted in the blue shift compared to bulk ZnSe as observed from the absorption spectra of particles dispersed in DMF. We obtained the photoluminescence spectra on these particles with two different excitation wavelength which shows broad band emission peak at 573 nm. Photoluminescence spectra taken with other excitation wavelength also gives sharp emission peaks at 484 nm, 530 nm, 551 nm and 600 nm.
Nonstoichiometry and luminescent properties of ZnSe crystals grown from the melt at high pressures
Journal of Crystal Growth, 2017
ZnSe homogeneity region was studied by direct physico-chemical method in 730-1320 K temperature range. It was established that the homogeneity region included stoichiometric composition and solidus lines both from Zn-and Se-rich sides demonstrated the retrograde behavior. Comparison of ZnSe nonstoichiometry with ionized defect concentrations at S ZnSe-L (Zn)-V equilibrium had let us assert that at the examined conditions the dominant point defects are electrically neutral. Nonstoichiometry analysis of ZnSe crystals grown from melt under high pressure and from vapor by the Markov-Davydov technique showed that there were Se-excess over stoichiometry in melt grown ZnSe and Zn-excess close to stoichiometry in vapor grown crystals.
Vapor growth and characterization of Cr-doped ZnSe crystals
Journal of Crystal Growth, 1999
Cr-doped ZnSe single crystals were grown by a self-seeded physical vapor transport technique in both vertical (stabilized) and horizontal con"gurations. The source materials were mixtures of ZnSe and CrSe. Growth temperatures were in the range of 1140}11503C and the furnace translation rates were 1.9}2.2 mm/day. The surface morphology of the as-grown crystals was examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Di!erent features of the as-grown surface of the vertically and horizontally grown crystals suggest that di!erent growth mechanisms were involved in the two growth con"gurations. The [Cr] doping levels were determined to be in the range of 1.8}8.3;10 cm\ from optical absorption measurements. The crystalline quality of the grown crystals were examined by high-resolution triple-crystal X-ray di!raction (HRTXD) analysis.
physica status solidi (a), 2002
ZnSe single crystals, obtained by the Solid Phase Recrystallization (SPR) method under three different pressure conditions, 10 and 5 atm of Se, and 2 atm of argon, have been investigated by means of photoluminescence (PL) and optical microscopy. Special attention has been paid to the surface state of the samples. Samples recrystallized under 10 atm of Se present the best rate between the PL response for the excitonic zone and the deep level one that shows a "clean" PL emission without significant peaks and/or bands. The presence of slip bands has been detected and analysed by means of optical microscopy and photoluminescence. In order to study the changes introduced by post growth thermal treatments, we have analysed the low temperature PL response on SPR samples after different thermal treatments. Striking changes have been detected in the PL response before and after the thermal treatment. The involved mechanisms have been studied.