Polarity determination of CdTe(111) orientation grown on GaAs(100) by molecular beam epitaxy

Since the crystallographic polarity of the CdTe(111) buffer layer can change the growth conditions of HgCdTe, HgMnTe, and HgZnTe, it is important to know the polarity of the terminating of the CdTe(111)∥GaAs(100) substrates. It is especially important since this composite substrate appears as the candidate for replacement of CdTe for epitaxial growth of Hg-based II-VI compounds. The identification of the orientation is reported here for the first time by x-ray photoelectron spectroscopy, chemical etching, and in situ electron diffraction. From all three techniques, the results show unambiguously that the CdTe(1̄1̄1̄)B face (Te face) is the terminating surface for CdTe(111) growing on GaAs(100) substrates.