硅衬底GaN基电力电子器件中复杂的缺陷问题，制约着器件电学性能的提升。目前主流电学测量方法只能观测输运特性中的多种缺陷态的综合效应，难以精细区分不同缺陷的特征贡献，限制了对缺陷态本质的深入认识。本项目采用光学调控与电学测量相结合的实验手段，通过对HEMT不同功能层中缺陷态荷电状态的选择性调制，实现对原生缺陷态和大电流/高电场条件下新生缺陷态的分布位置识别，进而结合光学和电学特性揭示缺陷态的本质；利用时间分辨的光电探测技术，深入分析HEMT结构中表面态、界面态以及AlGaN和GaN材料内部点缺陷与扩展缺陷对2DEG载流子复合、散射、俘获、隧穿等行为的动力学特征，研究AlGaN和GaN功能层、AlGaN表面及AlGaN/GaN界面不同区域所特有缺陷态对2DEG载流子输运行为的影响机理。本研究通过对缺陷态本质及其对2DEG载流子输运特性影响机理的深入认识，进而指导高质量材料生长和高性能器件研制。

In this project, optical and electrical techniques are employed to investigate defects in AlGaN/GaN HEMT on Si, and the impacts of different defects on the transport properties of the 2DEG carriers. By incorporating adjustable optical penetration method into electrical measurements, the charge state of defects in different layers of a HEMT structure can be intentionally modified, which enables identification of the position of defects specific to AlGaN, GaN, AlGaN surface or AlGaN/GaN interface. With the position identification and the integrated characterization of both the optical and electrical properties, the structural and electronic nature of the defects can be revealed. Based on the revealed nature and their location distribution of the defects, the formation mechanism of new defects caused by high-power, high-voltage conditions in working HEMT will also be investigated, focusing on their spatial distribution and the its effect on 2DEG transport behaviors. Optoelectrical experiments with both space and time resolution will be performed to identify the impacts of different surficial/interfacial states and those in AlGaN and GaN on different dynamical interactions including recombination, scattering, trapping, and tunneling, and the interacting nature on transporting electrons in 2DEG will be understood. The discovery and conclusions of this study are believed to provide critical guidance for material growth and structure design of GaN-based devices on silicon.