CdTe-HgTe multilayers grown by molecular beam epitaxy

Abstract

Monocrystalline multilayers CdTe-HgTe have been grown for the first time using the molecular beam epitaxy (MBE) technique. A multilayer consisting alternately of CdTe (44 Å thick) and HgTe (180 Å thick), repeated 100 times, has been grown at 200 °C with a good crystal quality. As for epilayers grown by MBE the crystallinity of the multilayers is improved by a raise in substrate temperature; moreover, the crystal quality is higher for HgTe than for CdTe up to 200 °C. An upper limit of 40 Å for the interdiffusion depth between HgTe and CdTe layers has been determined from Auger electron spectroscopy and ion microprobe profiling measurements carried out on a 13 1/2 -period multilayer, each period consisting of 150 Å for the CdTe layer and 400 Å for HgTe layer. We have also observed that no decrease occurs in the peak-to-valley ratio Auger signals if the focus of the electron gun is maintained at the center of the ion crater, during all the analysis, using the secondary electron image.