基于铟镓氮量子点的宽光谱及可调谐发光器件

Quantum dots have the potential to realize wide-spectrum light-emitting owing to the unique state-density distribution and the energy-level filling effect. It is an effective approach to broaden the spectrum of red, green and blue (RGB) light-emitting diodes (LEDs) using InGaN quantum dots in place of the quantum-wells active region, and hence increase the color rendering indices of white LEDs. In this project, growth mechanics of InGaN quntum dots will be studied to realize the material growth regulation and the light-emission spectrum tuning. Then red, green, and blue broadband LEDs based on InGaN quantum dots will be fabricated and combined to white LEDs, which will have good color rendering and be fit for smart tuning. The strong quantum-confiment effect of InGaN quantum dots will be also explored to achieve high-efficiency ultravoilet-emitting replacing AlGaN. The broadband emission property, combined with the wavelength-selectivity property of optical microcavity, make quantum dots a good choice to fabricate wide-spectrum tunable light-emitting devices. By incorporating resonant-cavity consisting of AlGaN/air Bragg reflector and Al mirror, ultraviolet resonant-cavity light-emitting diodes will be fabricated to achieve broad-range tunability.

量子点由于独特的态密度分布和能级填充效应而具有宽光谱发光特性。以InGaN量子点代替量子阱有源区，能够展宽红绿蓝（RGB）三基色发光二极管（LED）的发光光谱，是提高RGB白光光源显色指数的一条有效途径。本项目从研究InGaN量子点的生长机制入手，研究其发光光谱调控，进而制备基于InGaN量子点的宽光谱RGB LED，获得高显色性并适合智能调控的白光照明光源。此外，制备低In组分的InGaN量子点，借助量子点的强量子限制效应，代替AlGaN作为有源介质实现紫外发射，提高紫外发光器件的发光效率。结合光学微腔的选频特性，在InGaN量子点紫外LED中加入由AlGaN/空气隙和铝反射镜组成的谐振腔，制备具有宽光谱调谐范围的紫外共振腔LED。本项目为提高RGB LED显色性、提高紫外LED发光效率和实现宽光谱调谐范围提供了新的研究思路和解决方案。

本项目提出利用量子点能级填充效应制备GaN基宽光谱及可调谐发光器件。本项目围绕InGaN 量子点生长以及基于InGaN 量子点的宽光谱和可调谐发光器件开展研究, 通过本项目的实施，研究了生长温度、生长时间和中断时间等生长参数对量子点形貌和发光光谱的影响，掌握了自组织InGaN量子点的生长规律；结合对InGaN量子点的能级填充效应的理论模拟分析，通过调控生长参数实现了InGaN量子点的光谱调控；研制出基于InGaN量子点的宽光谱LED，其光谱宽度比常规MQW LED显著展宽；实现了基于GaN量子点的紫外发射；根据电化学腐蚀对掺杂浓度的选择性，用电化学腐蚀方法制备了GaN多孔材料和高Al组分AlGaN多孔材料，以及基于多孔GaN材料的高反射宽光谱蓝、绿光DBR；在多孔GaN DBR模板上制备了蓝光RCLED。本项目的实施为提高RGB LED显色性、提高紫外LED发光效率和实现宽光谱可调谐开辟了一条新的途径。