本课题针对固态照明、生化探测、激光引信和材料加工等重大科技领域中对半导体短波长激光器的迫切需求，重点解决在近紫外波段InGaN量子阱中In组分减少导致的局域态密度降低、对阱内载流子限制作用变弱、有源区载流子泄漏增强的问题，研究阱内量子限制作用的增强机制并对载流子泄漏进行抑制，包括增强阱内In组分分布的不均匀性以提高局域态密度，用(Al, In)GaN代替GaN作为垒层以提高势垒高度，在AlInGaN四元合金量子阱中掺入更多的In组分以提高局域态密度，提高多量子阱的界面陡峭度来降低界面态对复合发光的影响，采用极化反转电子阻挡层抑制电子泄漏等；同时结合紫外波段的有源区结构特点和激光器研制的需要，对p型掺杂等科学问题进行研究，最终实现波长小于400 nm GaN基近紫外激光器的电注入激射，脉冲峰值功率达到5 W，为国家提供核心的半导体近紫外光源。

Based on the significance of short-wavelength laser diodes in many fields, such as solid-state lighting, biochemical detection, laser fuse and material processing, this proposal concentrates on the theoretical design and device fabrication of GaN-based laser diodes in near-ultraviolet region. Compared with blue and green region, the indium content of InGaN quantum well in this wavelength region decreases to a relatively low value. As a result, the exciton localization state density originating from the In composition fluctuation in InGaN quantum well correspondingly decreases. The quantum confinement effect of carriers is thus weakened in GaN/InGaN multiple quantum well (MQW) active region and vertical electron leakage from active region to p-type region is correspondingly enhanced. In order to address this problem, the project is focusing on mechanisms and possible solutions about how to enhance the quantum confinement effect of carriers in InGaN quantum wells simultaneously with the suppression of vertical electron leakage, including increasing In composition fluctuation to increase exciton localization state density, replacing GaN quantum barrier with quaternary (Al, In)GaN layer to raise the band offset and barrier height in (Al, In)GaN/InGaN MQW, introducing more In content in AlInGaN quantum wells to increase exciton localization state density, improving (Al, In)GaN/(Al)InGaN interface abruptness to reduce the adverse impact of interface states on radiation recombination in quantum wells, changing the polarization field in AlInGaN electron blocking layer to eliminate the energy band bending effect. Some other solutions to the key problems in GaN-based ultraviolet laser diodes, such as the p-type doping, are also proposed to adapt the special wavelength and device structure in near-ultraviolet region. With the project approval and implementation, the stimulated emission of GaN-based laser diodes in near-ultraviolet region with peak wavelength <400 nm and peak power >5 W will be realized under electrical injection.