Identification of tellurium precipitates in cadmium telluride layers grown by molecular beam epitaxy

Abstract

The low-temperature growth of crystalline layers of CdTe on InSb substrates by molecular beam epitaxy has been investigated using transmission electron microscopy. It has been shown that while layers grown at substrate temperatures of ∼180–200 °C are generally single crystal and of good structural quality, layers grown at temperatures of ∼150 °C, although initially single crystal, rapidly become polycrystalline with increasing layer thickness. The mechanism responsible for this growth breakdown at low temperatures is shown to be the formation of second phase precipitates. These precipitates have been identified using diffraction analysis as the low-pressure, hexagonal phase of elemental Te.