Growth and characterization of ZnTe single crystal via a novel Te flux vertical Bridgman method

In this work,an Ⅱ-Ⅵ group semiconductor zinc telluride(ZnTe) single crystal is prepared by a novel vertical Bridgman method using Te as flux.The initial mole ratio of Zn/Te=3:7 is designed for raw material synthesis.ZnTe polycrystalline combined with rich Te is effectively fabricated through rocking technique at 1100℃.A Φ 25 mm × 65 mm ZnTe boule is successfully grown under a~40 ℃·cm^(-1) temperature gradient with a growth speed of 5 mm·day^(-1).The as-grown ZnTe crystal has a standard 1:1 stoichiometric ratio and pure F43 m phase structure.The maximum transmittance perpendicular to(110) plane is about 64%,and the band gap(E_(g)) is tested to be 2.225 eV.Terahertz(THz) examination results demonstrate that the time of the highest THz signal is around 17 ps and the frequency of the highest THz transmission is about 0.78 THz,implying that the ZnTe crystal grown by the present Te flux vertical Bridgman method has a good feasibility for THz application.

Vertical Bridgman Seeded Growth of Cd_(1-x)Zn_xTe Crystals

The method of vertical Bridgman seeded growth of Cdi.Zn.Te crystals was studied. This method ispromising in obtaining large size single crystals and improving the crystal structure. However, some prob-lems such as seeded growth failurc exist at present.(111)-oriented Cd_(0.96)Zn_(0.04)Te single crystal substrateswith size greater than 15×15 mm￣2 arc obtained. The FWHM ranges from 18 to 66 arc.sec and theresistivity is greater than 10￣6 obmem.

Parameter Optimization of CdZnTe Crystal Growth Simulated by Finite Element Method

During the crystal grown by VBM, the solid/liquid interface configurations greatly influence the quality of as-grown crystals. In this paper, finite element method (FEM) was used to simulate the growth process of CdZnTe crystal. The effects of different crucible moving rates and temperature gradient of adiabatic zone on crystal growth rate and solid-liquid interface configuration were studied as well. Simulation results show that when crucible moves at the rate of about 1mm/h, which is nearly equal to crystal growth rate, nearly flat solid/liquid interface and little variation of axial temperature gradient near it can be attained, which are well consistent with the results of experiments. CdZnTe crystal with low dislocation density can be obtained by employing appropriate crucible moving rate during the crystal growth process.

Growth,crystalline quality and transition variation of ternary Pb(In_(1/2)Nb_(1/2))O_(3)-Pb(Mg_(1/3)Nb_(2/3))O_(3)-PbTiO_(3) ferroelectric crystals

Bulk crystals of high Curie temperature(T_(C))24Pb(In_(1/2(Nb_(1/2))O_(3)-43Pb(Mg_(1/3)Nb_(2/3))O_(3)-33PbTiO_(3)(24PIN-43PMN-33PT)with 55 mm in diameter and 130mm in length were reproducibly grown by the bottom-seeded Bridgman method.The X-ray diffraction(XRD)spectrum indicated that the as-grown crystal was a single phase with rthombohedral structure at room temperature,the domain morphology and the phase transition sequence of R→T→C were observed,the full width at half maximum(FWHM)of X-ray rocking curve of(002)face was about 0.77°,and the defect density was inferred to 2.56×10^(10)cm^(-2).The measured density of the as-grown crystals was very close to the theoretical one.Variation of the transition temperature of the as-grown crystals along the growth direction revealed that T_(C) increased linearly along the growth direction and rthombohedral to tetrahedral phase transition temperature(T_(RT))gradually decreased in the middle part of the ingot.