Molecular beam epitaxial growth of high quality ZnSe on (100) Si

ZnSe films have been grown by molecular beam epitaxy for the first time on argon ion sputtered and annealed (100) Si substrates, the simultaneous sputtering and annealing process being performed at a substrate temperature of 400 °C. The sputtered and annealed Si substrates were atomically clean as determined by Auger electron spectroscopy analysis, and exhibited a streaky, reconstructed (2×1) reflection high-energy electron diffraction (RHEED) pattern. Films grown with both the constituent element (Zn and Se) fluxes set to provide a growth rate of ∼0.6 μm/h at initiation of growth were polycrystalline, the crystallites being strongly oriented in the [111] direction as determined by RHEED observations. Parallel epitaxy, i.e., (100) ZnSe∥(100) Si was achieved when the growth rate at initiation of growth was close to zero. Epitaxial ZnSe films exhibited dominant bound excitonic 4.2 K photoluminescence (PL) emission at 2.788 eV (Iz1). The Iz1 peak was also detected in the PL spectra of polycrystalline films; however, its absolute intensity was reduced by over two orders of magnitude.