Molecular beam epitaxial growth of PbTe and PbSnTe on Si(100) substrates for heterojunction infrared detectors

We have investigated the molecular beam epitaxial (MBE) growth of the IV-VI compounds PbTe and PbSnTe directly on Si(1 0 0) substrates, by in situ reflection high energy electron diffraction characterization. PbTe/Si(1 0 0) heterostructures were previously obtained only by hot wall epitaxy, and were shown to work as room temperature heterojunction photovoltaic detectors for the mid-infrared band (3-5 mum). Present work has shown that IV-VI single crystal layers, crack-free and as thick as 0.5 mum, can be obtained by MBE on thermally deoxidized Si(1 0 0) substrates. The layers were found to be rotated by 45 degrees relative to the substrate azimuthal orientation, and their quality depended on the use of an additional Te flux. (C) 2001 Elsevier Science B.V. All rights reserved.