低维AlGaN异质界面微结构及其极化调控研究

Low-dimensional nano-structure aluminum gallium nitrides (AlGaN), as the key materials of a new generation of optical and electrical devices, have attracted much research interests. Heterointerface microstructure of AlGaN and its polarization modulation are the key problems to achieve high-performance unction devices. The project will focus on the characteristics of low-dimensional AlGaN heterojunction interface with the method of combining the structural design, performance prediction and Experimental verification. For some typical AlGaN structures (Such as, GaN/AlN or GaN/Al0.5Ga0.5N quantum wells, quantum wires and quantum dots), their polarization state of the non-ideal heterojunction interface, the microscopic characteristics and its formation mechanism will be carefully examined; Further studies on interfacial microstructure evolution and its polarization modulation will be executed during the process of the AlGaN structural change (phase change) induced by the external field (pressure, temperature, etc.). By systematic analysis of the correlations between interfacial microstructure and polarization modulation, it will clarify the physical essence of the effects of the structure, scale, impurities and defects of AlGaN on the interfacial characteristics, and it will find out the controllable behavior of the polarization modulation in interface of the low-dimensional nano-structured AlGaN. Ultimately, considering the actual device application environment， it is expected that the predictive models, experimental methods and technical solutions to improve the electrical and optical properties of low-dimensional AlGaN can be brought forward through the design of the interface polarization.

低维铝镓氮（AlGaN）纳米结构作为新一代光电器件核心，引发了人们的研究热潮。界面微结构特性设计及其极化调控是实现高性能低维AlGaN功能器件的关键。本项目将围绕低维AlGaN异质界面特征，采用结构设计、性能模拟与实验验证相结合的方法，重点研究低维AlGaN典型结构（GaN/AlN与GaN/Al0.5Ga0.5N量子阱、量子线及量子点）非理想异质界面的极化状态、微观特征及形成机制；进一步研究外场（压力、温度等）诱导下低维AlGaN结构变化（相变）过程中界面微结构演化机制及其对极化调控的影响规律。通过系统地研究异质界面微结构与极化调控二者间的相互依赖关系，明晰AlGaN的结构、尺度、杂质及缺陷影响界面特性的物理实质，澄清低维AlGaN中纳米结构界面极化调控的行为规律；提出通过异质界面极化设计实现低维AlGaN结构电学与光学性能提高的有效预测模型、实验手段及技术方案。

低维铝镓氮（AlGaN）纳米结构作为新一代光电器件核心，引发了人们的研究热潮。界面微结构特性设计及其极化调控是实现高性能低维AlGaN功能器件的关键。本项目围绕低维AlGaN异质界面特征，采用结构设计、性能模拟与实验验证相结合的方法，重点研究低维AlGaN典型结构的极化状态、微观特征及形成机制；进一步研究低维AlGaN结构变化过程中界面微结构演化机制及其对极化调控的影响规律。通过系统地研究异质界面微结构与极化调控二者间的相互依赖关系，明晰AlGaN的结构、尺度、杂质及缺陷影响界面特性的物理实质，澄清低维AlGaN中纳米结构界面极化调控的行为规律；提出通过异质界面极化设计实现低维AlGaN结构电学与光学性能提高的有效预测模型、实验手段及技术方案。通过理论研究，成功地实现了具有高稳定性的GaN反转界面，不仅很好地消除了界面极化，同时有利于实现界面处的电子与空穴分离，有望应用于新型光伏或光催化纳米光电器件。系统研究了缺陷与空位对于AlGaN异质界面微结构影响及极化调控特性。对于超晶格的能带和电子态密度，阴离子空位相对于阳离子空位，其影响将更为明显。为了抑制界面处阴离子空位的形成，也为了保证AlN/GaN超晶格预期电学或光学性能，在制备AlN/GaN超晶格时，最好在富N环境中进行。此外，通过界面微结构控制方法，采用嵌入挛晶界自模板诱导生长，成功地实现了高度取向单根纳米线的制备，为大规模低成本纳米线器件的研制提供了一种新的制备方法与技术路线。我们的项目研究成果将为低维AlGaN器件的设计与研发提供有价值的理论依据与实验指导。