Structural and optical properties of high-quality ZnTe homoepitaxial layers

The structural and optical properties of high-quality homoepitaxial ZnTe fi lms are investigated. A substrate surface treatment using diluted HF soluti on plays a key role in growing device-quality ZnTe layers. X-ray diffractio n analysis of ZnTe epilayers based on the crystal-truncation-rod method sug gests that a homoepitaxial ZnTe film grown on a HF-treated substrate can be regarded as an ideal truncated crystal without an interfacial layer, while a ZnTe layer grown on a substrate without HF treatment suggests the presen ce of an interfacial layer which may lead to degraded crystallinity of ZnTe overlayers. The crystal quality of the homoepitaxial ZnTe layers with HF t reatments are characterized by an extremely narrow x-ray diffraction linewi dth of 15.6 arcsec and dominant very sharp excitonic emission lines with dr amatically reduced deep-level emission intensity in the photoluminescence ( PL) spectrum. Three bound excitonic emission lines at neutral acceptors are observed in the PL from the high-quality ZnTe homoepitaxial layers in addi tion to the free-exciton emission line, suggesting the presence of three di fferent kinds of residual acceptor impurities. (C) 2000 American Institute of Physics. [S0003-6951(00)02635-8].