Epitaxy induced phase stabilization: a comparative experimental and elasticity-based theoretical study on MBE grown PbSe/CaF2/Si epilayer

Modern epitaxial growth techniques show that material-phase stabilization can be achieved by epitaxial growth provided that suitable substrate (s) are used. Buffer layers (BL) play a vital role in epitaxial growth optimisation. By applying through the BL/s heterostructure continuity conditions on relevant strain-related features, we perform a self-consistent growth-optimisation strategy involving BL compositions. The calculation of these strain-related phase-dependent features enables to achieve an approach of as-grown material phase determination based on epitaxy experiments and theoretical previsions. To illustrate this methodology, we have investigated the lead salt IV–VI PbSe/CaF₂/Si(111) epilayer grown by MBE. For the optimised BL, a thin CaFSe layer has been grown under Se flux of CaF₂ layer before deposition of the PbSe layer. The efficiency of the continuity conditions in optimising MBE growth is shown by characterising all samples by high-resolution X-ray diffraction, atomic force microscopy for structural quality and Hall effect for electrical properties.