面向深紫外LED的纳米图案化蓝宝石衬底高效飞秒激光加工

立足于现有的飞秒激光加工制备蓝宝石微纳结构和相关光物理机理的研究基础，面向应用于高效率深紫外LED的纳米图案化蓝宝石衬底（NPSS）的制备难题，本项目提出利用飞秒激光加工制备NPSS。围绕激光加工制备蓝宝石衬底中存在高精度与高效率的矛盾，提出了激光扫描实现大宽幅印刷加工思路；结合飞秒激光诱导表面等离激元共振和纳米结构诱导远场激光近场加强的激光与材料作用的新机理以及空间光调制多焦点分光的新技术，提出了大幅宽激光表面诱导烧蚀印刷加工方案、“种子结构”诱导远场激光近场加强印刷加工以及刻蚀辅助的空间光调制器多焦点光场蚀点印刷加工三种制备方案，实现表面图案结构周期小于800nm的NPSS的高效可控制备。利用制备的高质量的NPSS，通过MOCVD外延生长技术，获得外量子效率超过10%的深紫外LED。

Based on the reported papers foundation of sapphire micro-nanostructure and related photophysical mechanism for femtosecond laser processing, and facing the difficulty of preparing nano-patterned sapphire substrate (NPSS) applied to high-efficiency deep ultraviolet LEDs, this project proposes to use femtosecond laser processing to prepare NPSS. Concerning the contradiction between high precision and high efficiency in the preparation of sapphire substrate by laser processing, a laser scanning mode for large-format printing processing is proposed. Combined with the new laser-material interaction mechanism of femtosecond laser-induced surface plasmon resonance and nanostructure-induced far-field laser near-field enhancement, and new technology of spatial light modulation multifocal beam splitting, three preparation schemes including laser-induced surface plasmon ablation printing processing, "seed structure" induced far-field laser near-field enhanced printing processing, and etching-assisted spatial light modulator multifocal light field etching point printing processing are adopted to achieve efficient and controllable preparation of NPSS with a surface pattern structure period less than 800nm. Utilizing the prepared high-quality NPSS and MOCVD epitaxial growth technology to achieve high-performance deep ultraviolet LED with external quantum efficiency exceeding 10%.