Heteroepitaxial growth of wurtzite InN films on Si(111) exhibiting strong near-infrared photoluminescence at room temperature

Abstract
High-quality InN epitaxialfilms have been grown by nitrogen-plasma-assisted molecular-beam epitaxy on Si(111) substrates using a double-buffer technique. Growth of a (0001)-oriented single crystalline wurtzite–InN layer was confirmed by reflection high-energy electron diffraction,x-ray diffraction, and Raman scattering. At room temperature, these films exhibited strong near-infrared (0.6–0.9 eV) photoluminescence(PL). In addition to the optical absorption measurement of absorption edge and direct band nature, the PL signal was found to depend linearly on the excitation laser intensity over a wide intensity range. These results indicate that the observed PL is due to the emission of direct band-to-band recombination rather than the band-to-defect (or impurity) deep emission.