基于湿法剥离的AlGaN基深紫外LED在高强度双轴应变下的发光模式调控

AlGaN基深紫外LED对包括新冠病毒在内的细菌和病毒均有较强的杀灭作用。然而，深紫外LED发光中存在较高比例沿侧面传播的TM偏振光，导致光提取效率通常低于15%。虽然理论上可以通过应变调制TM偏振光的发光比例，但受限于蓝宝石衬底的刚性特征，实验上可施加的应变强度很低，利用强应变(＞1%)调控发光模式的手段和规律缺失。为突破传统研究在应变强度方面的限制，本项目基于申请人良好的前期基础和条件，创新性地采用电化学腐蚀方法将280 nm深紫外LED的蓝宝石衬底剥离，利用柔性衬底对薄膜深紫外LED施加高强度的机械应变，研究薄膜深紫外LED在强双轴应变(＞1%)条件下的发光机制和调控规律，获得断裂强度范围内应变强度和TM偏振光发光比例的定量关系，在此基础上发展出利用高温共晶后永久保留的高强度压应变降低深紫外LED中TM偏振光发光比例的实验解决方案，为提高深紫外LED的出光效率提供理论指导和实验支撑。

AlGaN-based deep ultraviolet light-emitting diodes(DUV LED) has strong sterilization and disinfection including COVID-19.However, there is a high proportion of TM-polarized light propagating along the side in DUV LED, which leads to a low light extraction efficiency, which usually less than 15%. Although it is theoretically possible to modulate the emission ratio of TM-polarized light by strain, the strain intensity that can be applied in the experiment is very low and the methods and rules of using strong strain (>1%) to regulate the emission mode are missing, due to the rigid sapphire substrate. To breakthrough the limitation of traditional research on the strain intensity, the project is based on the preliminary research basis and experiment conditions, the innovation in the electrochemical etching method to lift-off the 280-nm DUV LED from sapphire substrate, high intensity mechanical strain applied by flexible substrate, research in the luminescent mechanism and control rules under strong strain (> 1%), obtained the quantitative relation with strain intensity and TM-polarized light proportion within rupture strength, on this basis, an experimental solution is developed to reduce the emission ratio of TM-polarized light in DUV LEDs by applying high compressive strain which is permanently retained by high temperature eutectic, which provides theoretical guidance and experimental support for improving the light emission efficiency of DUV LEDs.