Effects of in situ thermal annealing on the structural, optical, and electrical properties in Hg 0.7Cd 0.3Te epilayers grown on CdTe buffer layers

Abstract

Scanning electron microscopy (SEM), Fourier transform infrared (FTIR) transmission, and Hall effect measurements were performed to investigate the structural, optical, and electrical properties of as-grown and in situ-annealed Hg 0.7Cd 0.3Te epilayers grown on CdTe buffer layers by using molecular beam epitaxy. After the Hg 0.7Cd 0.3Te epilayers had been annealed in a Hg-cell flux atmosphere, the SEM images showed that the surface morphologies of the Hg 0.7Cd 0.3Te thin films were mirror-like with no indication of pinholes or defects, and the FTIR spectra showed that the transmission intensities had increased in comparison to that of the as-grown Hg 0.7Cd 0.3Te epilayer. Hall-effect measurements showed that n-Hg 0.7Cd 0.3Te epilayers were converted to p-Hg 0.7Cd 0.3Te epilayers. These results indicate that the surface, optical, and electrical properties of the Hg 1 − x Cd x Te epilayers are improved by annealing and that as-grown n-Hg 1 − x Cd x Te epilayers can be converted to p-Hg 1 − x Cd x Te epilayers by in situ annealing.