Band offsets of ZnO/PbTe heterostructure determined by synchrotron radiation photoelectron spectroscopy

Abstract

Accurate determination of the band offsets of a heterostructure is essential to its study and application. In this paper, we use synchrotron radiation photoelectron spectroscopy to determine the band offset of ZnO/PbTe heterostructure. The valence band offset is 2.56 eV, and the conduction band offset is 0.49 eV, which indicates that the heterostructure has a type-I band alignment. By performing the depth scanning measurement, we find there are two bonding structures at the interface of ZnO/PbTe heterostructure, corresponding to Pb-O bonding (low energy side) and Pb-Te bonding (high energy side). At the interface of ZnO/PbTe heterostructure, the conduction band offset is much smaller than the valence band offset which is conducive to the transportation of excited electrons in PbTe source layer to ZnO electrode. Due to the unique band structure the ZnO/PbTe heterostructure has potential applications in the fabrication of high efficiency solar cells, mid infrared detectors and lasers.