Photocurrent spectroscopy of a (0 0 0 1)GaN/AlGaN/(1 1 1)Si heterostructure

A crack-free GaN/AlGaN sample was grown on (1 1 1) Si by selective area metal-organic vapor-phase epitaxy method using an AlGaN intermediate layer. The electrical properties of the GaN/AlGaN/Si heterojunction diode were investigated with photocurrent spectroscopy at View the MathML source. It was found that the current–voltage characteristics depend on the thickness/composition of the intermediate layer. The photocurrent spectra indicated that the energy band of the n-type-doped Si substrate is lifted at the heterointerface, while it is flat in case of the sample grown on a p-type-doped Si. The depletion of the energy band in the n-Si at the heterointerface is attributed to the diffusion of Al during the growth.