Tham khảo tài liệu 'ferroelectrics characterization and modeling part 10', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 16 Valence Band Offsets of ZnO SrTiO3 ZnO BaTiO3 InN SrTiO3 and InN BaTiO3 Heterojunctions Measured by X-Ray Photoelectron Spectroscopy Caihong Jia1 2 Yonghai Chen1 Xianglin Liu1 Shaoyan Yang1 and ZhanguoWang1 1Key Laboratory of Semiconductor Material Science Institute of Semiconductors Chinese Academy of Science Beijing 2Key Laboratory of PhotovoltaicMaterials of Henan Province and School of Physics Electronics Henan University Kaifeng China 1. Introduction The heterostructures of wurtzite semiconductors and perovskite ferroelectric oxide integrate the rich properties of perovskites together with the superior optical and electronic properties of wurtzites thus providing a powerful method of new multifunctional devices. The electrical and optical properties of the heterostructures are strongly influenced by the interface band offset which dictates the degree of charge carrier separation and localization. It is very important to determine the valence band offset VBO of semiconductor ferroelectric oxides in order to understand the electrical and optical properties of the heterostructures and to design novel devices. In this chapter by using X-ray photoelectron spectroscopy XPS we determine the VBO as well as the conduction band offset CBO values of the typical semiconductor ferroelectric oxide heterojunctions such as ZnO SrTiO3 ZnO BaTiO3 InN SrTiO3 and InN BaTiO3 that are grown by metal-organic chemical vapor deposition. Based on the values of VBO and CBO it has been found that type-II band alignments form at the ZnO SrTiO3 and ZnO BaTiO3 interfaces while type-I band alignments form at InN SrTiO3 and InN BaTiO3 interfaces. For many years heterojunctions have been one of the fundamental research areas of solid state science. The interest in this topic is stimulated by the wide applications of heterojunction in microelectronics. Devices such as heterojunction bipolar transistors quantum well lasers and heterojunction field effect transistors FET already have a .
