The Effect of Thermal Treated GaSb Substrate for Epitaxial Growth of CdZnTe Film by Close-Spaced Sublimation Method

We reported an in-situ thermal treatment method to remove the natural oxides on GaSb (001) substrates for epitaxial growth of CdZnTe films by close-spaced sublimation. The effect of the thermal treatment on the morphology and composition of the GaSb substrate was analyzed using atomic force microscopy and X-ray photoelectron spectroscopy. The double crystal X- ray rocking curve was used to evaluate the crystalline quality of CdZnTe epitaxial films on thermal treated GaSb substrates. These results indicate that the natural oxides on GaSb substrates are a key factor in deteriorating the quality of CdZnTe films, and that thermal treatment is effective in removing the oxides to improve the crystalline quality of the epitaxial CdZnTe films. The optimized GaSb substrate with thermal treatment at 600 ℃ for 180 s can obtain high-quality epitaxial CdZnTe film with the full width of half maximum of double crystal X-ray curve of 94 arcsec, which approached the crystalline quality of bulk CdZnTe crystal ever reported.