具有二维光子晶体结构的高效氮化物谐振腔发光二极管研究

GaN-based resonant-cavity light-emitting diode (RCLED) has many advantages such as high efficiency, narrow output linewidth, circular output beam, improved temperature stability, and potential applications in high-speed optical communication, high-speed printing and scanning, and visible-light communication. However, the research on the GaN-based RCLED is still at the early stage due to the difficulties in fabrication process. The aim of this proposal is to develop high efficiency GaN-based RCLED with two-dimensional photonic crystals. To achieve this, efforts will be made toward the following three aspects. First, the key fabrication technologies including high reflectance contact to p-GaN, metal substrate electro-plating and laser lift-off techniques will be carefully studied to form a mature solution. Second, on this basis, we will fabricate the short-cavity devices through inductively coupled plasma etching and chemical mechanical polishing techniques, and investigate the relationship among efficiency, intra-cavity photon mode and the cavity length. Third, based on the above researches, we will further investigate the mechanism in changing the direction of photon transmission by photonic crystal, and fabricate the RCLED with designed photonic crystals. The photonic crystals will change the photons that in leaky and guided modes into resonant mode, resulting in the achievement of the high efficiency nitride-based RCLED.

Ⅲ族氮化物谐振腔发光二极管（RCLED）具有高效率、窄发射光谱、圆形光斑、温度稳定性等优点，在高速光通信、高速打印和扫描以及可见光通信方面有广泛的应用前景。但由于其制作困难，目前尚属于研究的起步阶段。本项目致力于研制具有二维光子晶体结构的高效氮化物RCLED，具体分下述三个方面来实现：1.深入研究RCLED制作中的关键工艺技术，包括p型高反射率电极，金属基板电镀，蓝宝石衬底激光剥离技术等，形成稳定的器件制备方案；2.在此基础上，结合感应耦合等离子体刻蚀和化学机械抛光技术制备出短腔长器件，并研究其出光效率、腔内光子模式与腔长之间的关系。3.在以上研究的基础上，研究和阐明光子晶体改变光子传输方向的机理，在氮化物RCLED上设计并制作与谐振模式相匹配的二维光子晶体结构，实现对泄漏和传输模式中光子的有效控制，促使这部分光子进入谐振模式，实现高效率的氮化物RCLED。

Ⅲ族氮化物谐振腔发光二极管（RCLED）具有高效率、窄发射光谱、圆形光斑、温度稳定性等优点，在高速光通信、高速打印和扫描以及可见光通信方面有广泛的应用前景。但由于其制作困难，目前尚属于研究的起步阶段。本项目主要在于通过研究氮化物RCLED的制备关键工艺以实现高效率的谐振腔发光器件。通过本项目的开展，获得以下研究成果：（1）制备了一种具有混合型量子阱的外延结构，使多量子阱中更多的阱层具有更为均匀的空穴注入，从而提高了发光二极管在大电流下的输出光功率，并可降低RCLED腔内的吸收损耗。（2）实现了高质量的金属反射镜、金属电镀衬底以及蓝宝石衬底的完整剥离等，获得了高效大功率发光二极管并为制备高效的RCLED提供了良好的基础。（3）利用纳米压印系统制备了结构完整的二维光子晶体结构，实现对不同波长的发光二极管的调制，为进一步制备具有光子晶体结构的光电子器件提供了一定的基础。4）研究影响RCLED出光效率的几个关键因素，通过优化量子阱有源区在光场中的位置，腔长大小以及光子晶体结构参数，大幅提高了RCLED的效率并获得了光谱纯度高，发散角小的绿光RCLED。