蓝宝石作为三族氮化物最常用的外延衬底，其导电、导热性差的缺点制约着三族氮化物材料和器件的发展。目前将氮化镓(GaN)从蓝宝石上分离最常用的激光剥离工艺存在阈值高、残余应力大、理论模型不完善等问题。近期，我们采用碳纳米管(CNT)阵列铺设在蓝宝石衬底上，制备了CNT掩膜蓝宝石衬底（CPSS），并在CPSS上实现了高质量、应力可控、LED性能提升的材料、器件的MOCVD外延。同时，初期的激光剥离实验发现，CNT阵列可以有效地降低剥离阈值，减少损伤。因此，本项目提出一种利用CNT调节GaN与蓝宝石界面，实现低阈值、小损伤、低残余应力的激光剥离工艺。项目具体实施中，研究CNT在激光剥离中起的作用，不同CNT分布和CNT特性对剥离阈值、晶体损伤、残余应力的影响，制作高性能垂直结构LED，同时完善激光剥离模型。本项目的研究成果将有助于高性能VCSEL、垂直结构LED、柔性LED及自支撑GaN的研究。

Sapphire, as the most favorable substrate for III-nitride materials, suffered its inferior electrical and thermal conductance. Laser lift off (LLO), as the-state-of-the-art methodology to exfoliate GaN from sapphire was, however, exhibiting high threshold energy, severe crystalline degradation, large residual stress, and defective simulation theory. Recently, carbon nanotube (CNT) arrays were utilized by us to fabricate Carbon nanotube Patterned Sapphire Substrate (CPSS). High-quality, stress tunable GaN materials and enhanced performed LEDs were epitaxied on CPSS by MOCVD. Moreover, lower threshold energy and little residual stress were observed in GaN/CPSS LLO process. Therefore, in this project, CNT assisted LLO is announced to realize low threshold, little crystal damage and low residual stress process. Particularly, the physical mechanism of CNT assisted LLO and the effects of different CNT properties and patterns on LLO will be researched. The vertical structure LED based on LLO of CPSS/GaN would also be fabricated and characterized. Furthermore, a three-dimensional LLO simulation mode including stress calculation modules and anisotropy will be built in this project. The promising results and achievements will be positive and helpful for high-performed VCSEL, vertical LED, flexible LED and free standing GaN substrate.