具有全反射n电极的空腔型倾斜侧壁深紫外LED的研究

深紫外LED可以广泛应用于杀毒消菌和通信等领域，《水俣公约》促使深紫外LED的全面应用更是迫在眉睫。但是深紫外LED非常低的光提取效率严重限制了其应用。这是由于传统高铝组份AlGaN基深紫外LED中存在大量难被提取的TM模极化光和高吸光材料。针对当今金属反射镜型倾斜侧壁提高TM模极化光提取效率的优缺点，本课题以时域有限差分模拟理论为指导，提出用AlGaN与空气间高折射率差界面代替金属反射镜对TM模极化光进行全内反射和菲涅尔散射，从而避免倾斜侧壁的金属吸收并保留高散射特性；其次，理论表明nAlGaN中传播的导模大部分都是在nAlGaN/air的全反射角区域内反射。因此申请人拟利用全反射n电极减少n电极对光的吸收，通过全内反射增加n电极正面反射率并增加光逃离通道。总之，本课题提出利用独特的空腔型倾斜侧壁结构解决深紫外LED光提取效率低的问题的新途径，有望推动深紫外LED进一步发展和应用。

DUV LED can be widely applied in the sterilization and the communication and so on. The Minamata Convention prompt DUV LED be used and developed faster. However, the low light extraction efficiency for conventional DUV LED seriously limits its application. It is because a large number of TM-polarized light is emitted from high Al-content AlGaN material and many high absorbent materials in DUV LED. The inclined sidewall structure is very effective to improve TM-polarized light extraction efficiency. To further improve the inclined sidewall structure, the research item shall be instructed by finite difference time domain simulation theory and propose total internal reflection from the interface between AlGaN and air instead of metal reflector and Fresnel scattering to scatter TM-polarized light to avoid the metal absorption from inclined sidewall and retain the high scattering ability; In addition, there are high light absorption from n electrode for the conventional metal inclined sidewall structures. And the optical theory indicates that most of the guided modes propagated in nAlGaN are total reflected from nAlGaN/air. Therefore, the applicant intends to employ the omnidirectional n-electrode reflector to reduce the light absorbed and blocked by the n electrode, increase the frontal reflectivity of the n electrode through the total internal reflection and add the light escape channel. This research item will provide a new way to improve the efficiency of DUV LED, and is expected to promote a further development for DUV LED.