MBE growth of CdTe, Hg1−xCdxTe, and multilayer structures: Achievements, problems, and prospects

Abstract

In this review the reasons for pursuing MBE (molecular beam epitaxial) growth of multilayer structures involving CdTe and Hg1−xCdxTe films are discussed. One major reason is that the poor structural quality of commercially available CdTe substrate wafers leads to limitations and degradation in structural quality of homoepitaxial CdTe films and Hg1−xCdxTe films grown on CdTe substrates. Double-crystal x-ray rocking curve (DCRC) analysis and x-ray topography have been used to identify intrinsic defects in CdTe which are responsible for this degradation. Progress toward MBE growth of a Hg1−xCdxTe /CdTe/InSb multilayer structure, which avoids the use of CdTe wafers and is based on high-perfection InSb substrates, is described. It is seen that the iterative use of powerful characterization techniques such as DCRC analysis and cross-section transmission electron microscopy (XTEM) is essential to the development of such structures. Major challenges to the approach of MBE to preparation of multilayer structures are considered.