Determination of the interface band alignment of NiO/4H-SiC heterojunction for photodetector application

Abstract

The band alignment of NiO/4H-SiC heterojunction is firstly investigated by X-ray photoelectron spectroscopy (XPS) and transmission spectra measurements. The valence (ΔEV) and conduction band offset (ΔEC) are determined as 2.5±0.01 and 3.0±0.01eV, respectively, which is the result of considering the effect of interfacial band bending. Furthermore, the band alignment is evaluated to be staggered (Type-II), which gives rise to the confinement of electrons and holes in the NiO layer and 4H-SiC, respectively. Hence, the large ΔEC (ΔEV) values and the type-II band alignment can contribute to the separation of photogenerated carriers for optoelectronic applications.