In 0.2Ga 0.8N layers were directly grown on Si(111) substrate by plasma-assisted molecular beam epitaxy (PAMBE). Structural characteristics of the as-grown InGaN epilayers were evaluated high resolution X-ray diffraction and composition of InGaN was estimated from photoluminescence spectra using the standard Vegard's law. High-resolution X-ray photoemission spectroscopy measurements were used to determine the band offset of wurtzite-In 0.2Ga 0.8N/Si(111) heterojunctions. The valence band of InGaN is found to be 2.08 ± 0.04 eV below that of Si. The conduction band offset (CBO) of InGaN/Si heterojunction is found ~0.74 eV and a type-II heterojunction. © 2012 The Japan Society of Applied Physics.