ABSTRACT: This paper reports on a detailed study of the development of the close space sublimation method, which has been widely used
in the preparation of polycrystalline CdTe/CdS solar cells, as an epitaxial method for the growth of thick CdTe single crystal
films over 200μm on GaAs and Ge substrates for high-energy radiation detectors. The resulting microscopic growth phenomena in the process
are also discussed in this paper. High-quality single crystalline CdTe thick films were prepared with x-ray rocking curves
full width at half maximum (FWHM) values, which were ∼100arcsec on Ge substrates and 300arcsec on GaAs substrates. The quality
of thick films on Ge(100) showed a substantial improvement with nucleation in a Te-rich growth environment. No Te inclusions
in the CdTe films grown on GaAs(211)B and Ge(100) were observed with IR transmission imaging. Photoluminescence of CdTe/Ge
shows a large reduction in the 1.44eV defect energy bands compared with films grown on GaAs substrates. The film resistivity
is on the order of 1010Ωcm, and the film displayed some sensitivity to alpha particles.
Journal of Electronic Materials 04/2012; 38(8):1548-1553. · 1.47 Impact Factor
ABSTRACT: This paper reports, for the first time, the successful growth of 200 µm thick CdTe films on mis-oriented Ge(1 0 0) substrates by a cost-effective optimized close space sublimation method. It is found that, as the thickness increases to a few hundred micrometres, subgrains are formed probably as a result of the large density of dislocations and strain within the initial interfacial layers. The films are of high quality (x-ray rocking curve width ∼100 arcsec) and high resistance (∼10 9 cm), and are thus candidates for x-ray and γ -ray detectors.
J. Phys. D: Appl. Phys. 01/2009; 42:12004-4.
ABSTRACT: The growth of large-area bulk crystals of cadmium telluride and cadmium zinc telluride has been demonstrated using the combination
of a novel physical vapor transport growth system and heteroepitaxial seeding on GaAs wafers. X-ray diffraction studies show
the resulting material to be of extremely high quality despite the large lattice mismatch between the seed and the grown crystal.
This process should provide a reliable growth route for large-area large-volume single-crystal boules of cadmium telluride
and cadmium zinc telluride.
Journal of Electronic Materials 08/2008; 37(9):1460-1464. · 1.47 Impact Factor
ABSTRACT: This paper reports on the growth using a modified physical vapour transport technique of good epitaxial CdTe layers on GaAs(1 0 0), (1 1 1)A and (2 1 1)B substrates. FWHM values as low as 250 arcsec with growth rates of 10–20 μm/h were recorded for 20-μm-thick CdTe layers grown epitaxially on (1 1 1)A GaAs. The surface morphology of all the films was examined to measure the potential growth of high-quality thick films. Interfacial strain relaxation is studied by a combination of high-resolution X-ray diffraction (XRD) and etch profiling, which indicates that at a film thickness of ∼0.65 μm, there is an abrupt change in the mechanism. It implies that above this thickness, the strain energy has fallen below the threshold for dislocation formation.
Journal of Crystal Growth 310:1652-1656. · 1.73 Impact Factor