HETEROEPITAXIAL GROWTH OF MNS ON GAAS SUBSTRATES

Epitaxial growth characteristics of MnS onto GaAs substrates with different orientations have been investigated by X-ray diffraction and reflection high energy electron diffraction (RHEED). Growth of MnS films has been performed by molecular beam epitaxy (MBE). Epitaxial films of wurtzite type MnS (gamma-MnS) in a single phase have been grown on GaAs(111) substrates at 200-degrees-C. The epitaxial gamma-MnS films shows good crystallinity, where full width at half maximum (FWHM) of the X-ray rocking curve is lower than 100 arc sec. On the other hand, the films on GaAs(001) at the same growth temperature exhibit multiphase crystal structures of zinc-blende and rock-salt in early growth stages, and change the main structure to wurtzite with increasing thickness. Photoluminescence spectra of the gamma-MnS films at 77 K exhibit an orange emission band around 570 nm which is attributed to Mn2+ ions, and red emission bands around 620 and 690 nm which would be attributed to Mn2+ ion pairs. The band gap energy of the gamma-MnS was estimated to be 3.9 eV from the excitation spectra.