翻转脊型结构GaN基激光器制备研究

GaN-based laser diodes (LDs) have a great potential in laser lighting and laser display applications. In the conventional LDs, the ridge is fabricated from the p-side with a small area, often resulting in a high series resistance and a high thermal resistance. And the operation voltage and the junction temperature of conventional LDs are fairly high, which greatly affects the wall-plug efficiency and reliability of LDs. This proposal aims to fabricate GaN-based LDs with an inverted ridge structure. In the inverted ridge structure, the ridge is produced from the n-side, and the p-type ohmic contact is formed on the whole surface, and then bonded with a heat sink. As compared to the conventional LDs, the series resistance and the thermal resistance of LDs with an inverted ridge structure can be reduced remarkably. As the operation voltage, the threshold current and the junction temperature decrease significantly, the wall-plug efficiency and the reliability of LDs will be improved greatly. Upon the previous study of GaN-on-Si LDs, this proposal will focus on the control of electrical current path, optical field and heat dissipation in GaN-based LDs with an inverted ridge structure, for an electrically injected continuous-wave operation at room temperature.

GaN基激光器在激光照明和激光显示等领域具有广阔的市场应用前景。常规结构GaN基激光器的脊型在p侧，造成激光器串联电阻和热阻较大，激光器的工作电压和工作结温较高，严重影响了激光器的电光转换效率和可靠性。本项目提出制备翻转脊型结构GaN基激光器，在激光器的n侧制作脊型，p侧整面欧姆接触，并与热沉键合。该翻转脊型结构激光器具有串联电阻小、热阻小和刻蚀损伤少等优点，有望大幅降低激光器的工作电压、阈值电流和工作结温，提升激光器的电光转换效率和可靠性。本项目拟在已有Si衬底GaN基激光器的工作基础上，围绕翻转脊型结构GaN基激光器中的电流输运、光场调控和热传导等关键科学问题开展研究工作，优化激光器的结构设计，研究激光器中低阻率、弱吸收的p型层生长，调控激光器中的电流输运路径、光场分布和热传导，降低激光器的串联电阻、光损耗和热阻，实现高性能翻转脊型结构GaN基激光器的室温连续工作。

GaN基激光器在激光照明和激光显示等领域具有广阔的市场应用前景。常规结构GaN基激光器的脊型在p侧，造成激光器串联电阻和热阻较大，激光器的工作电压和工作结温较高，严重影响了激光器的电光转换效率和可靠性。本项目提出制备翻转脊型结构GaN基激光器，在激光器的n侧制作脊型，p侧整面欧姆接触，并与热沉键合。该翻转脊型结构激光器具有串联电阻小、热阻小和刻蚀损伤少等优点，有望大幅降低激光器的工作电压、阈值电流和工作结温，提升激光器的电光转换效率和可靠性。本项目在已有硅衬底GaN基激光器的工作基础上，围绕翻转脊型结构GaN基激光器中的电流输运、光场调控和热传导等关键科学问题，从激光器的结构设计、材料生长和器件制备等方面开展研究工作，完成了预期的研究目标。取得的主要研究成果如下：1）高质量硅基GaN材料及激光器材料，晶体质量处于国际前列；2）室温电注入连续激射的硅基GaN翻转脊型波导激光器，相关工作发表于ACS Photonics等国际学术期刊；3）国际首支室温电注入连续激射的硅基GaN微盘激光器，相关成果发表于Photonics Research和Optics Express等国际学术期刊。上述相关成果得到了Semiconductor Today等国际半导体专业媒体的持续跟踪报道。在本项目资助下，共发表致谢本项目的高质量学术论文12篇，申请国家发明专利5项（授权3项），培养研究生4名（博士研究生3名），参加III族氮化物半导体相关的国内外学术会议3次。