THE PBSE METASTABLE PHASE .1. THE GROWTH-MECHANISM

PbSe and PbSe:Cd films, grown by two different non-equilibrium growth techniques, laser-assisted deposition and electron-beam evaporation, on two different types of substrate, KCl and BaF2, are investigated. The crystal structure of the films is studied by x-ray and reflecting high-energy electron diffraction. On the basis of the structural investigations it is found that the films grown by both non-equilibrium techniques represent heterophase junctions between the metastable CsCl-type phase and the stable FCC phase. The growth mechanism is semiquantitatively discussed in the framework of Sirota's examinations of the formation of the metastable phases. The substrate type is found to influence only the metastable-phase lattice constant, which in turn determines the thickness of the metastable-phase sublayer.