In adlayer mediated molecular beam epitaxial growth and properties of a-plane InN on freestanding GaN

The role of the In adlayer on the morphological and structural properties of nonpolar a-plane InN films was elucidated during the plasma-assisted molecular beam epitaxy on freestanding GaN. Reflection high energy electron diffraction during In adsorption experiments on a-plane InN surfaces revealed a stable In adlayer coverage of similar to 2 ML. This In adlayer-mediated growth was responsible for achieving atomically smooth surfaces (rms roughness of < 1 nm), phase-pure material with lower x-ray rocking curve widths (Delta omega < 0.5 degrees), lower crystal mosaic tilt/twist, and decreased stacking fault densities, compared to N-rich conditions. The photoluminescence peak emission and band gap energy of the a-plane InN films were similar to 0.63 and similar to 0.7 eV, respectively.