Growth, structural, and optical properties of II-VI layers: (001) CdMnTe grown by molecular-beam epitaxy

Abstract

The growth of CdMnTe by molecular-beam epitaxy is described, including an in situ calibration of alloy composition by reflection high-energy electron diffraction intensity oscillation, which takes advantage of the larger sticking coefficient of Mn with respect to Cd. Layers are studied by photoluminescence, x-ray diffraction, transmission electron microscopy, and cathodoluminescence imaging. Relaxation of the mismatch strain occurs through different mechanisms, depending on the sign and magnitude of the mismatch. Once identified the characteristic features of the cathodoluminescence images are used to determine the critical thickness of layers of uniform composition or of more elaborate heterostructures. A heuristic criterion for the relaxation of mismatch strain in heterostructures incorporating layers of continuously varying composition is checked.