近年来，紫外发光二极管(LED)因其在环保固化、杀菌消毒等领域的应用受到了人们的广泛关注。然而，LED的有源层-基于AlGaN材料的多层量子阱(MQW)受极化电场影响，电子和空穴在势阱内的分布出现分离，导致了LED的辐射复合效率的降低，即所谓量子限阈Stark效应。针对此问题，本项目拟制备薄膜面内周期分布的AlGaN金属极性畴和氮极性畴，构建三维能带，并实现载流子在三维能带中的定向迁移，从而抑制、甚至消除量子限阈Stark效应。围绕这一目标，本项目拟从AlGaN薄膜的极性调控和界面优化入手，考察不同极性AlGaN生长形貌、Al组分含量、费米能、电荷分布和迁移规律，制备横向极性结构紫外LED，提高p型掺杂效率，改善欧姆接触性能，从而制备无量子限阈Stark效应影响的高效率紫外LED及其他新型氮化物光电子器件。

Ultraviolet light-emitting-diode (LED) has drawn numerous attentions recently due to its wide applications in UV curing and disinfection. Due to strong polarization effect in the AlGaN multiple-quantum-well (MQW), electron and holes separate apart in the quantum well regions, leading to decreased radiative recombination rate. This is called the “quantum-confined-stark-effect (QCSE)”. This project aims to introduce laterally distributed III- and N-polar domains in the AlGaN thin film, promoting the lateral transport of carriers in the “three-dimensional band diagram” of AlGaN MQW, and finally inhibit the QCSE. To fulfil these requirements, we will investigate the growth morphology, Al composition, fermi level, and carrier distribution and transport of III- and N-polar domains of the AlGaN via techniques such as polarity control and interface modulation. We will optimize the p-type doping efficiency of AlGaN and ohmic contact property, and finally fabricate QCSE-free high efficiency UV-LEDs and develop novel III-nitride based optoelectronic devices.