Determination of the valence band offsets at HfO(2)/InN(0001) and InN/In(0.3)Ga(0.7)N(0001) heterojunctions using X-ray photoelectron spectroscopy
The valence band offset (VBO) at a InN/In(0.3)Ga0.7N(0001) as well as HfO(2)/InN(0001) heterojunction is investigated by X-ray photoelectron spectroscopy using monochromated AlKa radiation. The InN and In(0.3)Ga(0.7)N films were grown using plasma-assisted molecular beam epitaxy, whereas HfO(2) layers were deposited by plasma-assisted electron beam evaporation. The VBOs were determined by analysing the core level binding energy and valence band maxima of bulk-like films as well as of In(0.3)Ga(0.7)N and InN layers covered with 5 nm thick overlayers of InN and HfO(2), respectively. The resulting VBO values are ~0.5 eV for the InN/In(0.3)Ga(0.7)N heterojunction and ~0.9 eV in the case of the HfO(2)/InN heterointerface.