基于单晶n-ZnO/p-AlGaN LED结构的谐振光栅制备DFB激光器的基础研究

Recent, an exciting research project about the laser communication between a 400-kilometer faraway satellite and a receiving station was carried out by NASA of USA. In 3.5 second a high definition video was sent from the satellite to the receiver by a laser beam, which demonstrates that the transmission speed of the laser communication in this project is more than 1000 times faster than the traditional radio communication. It indicates a huge application prospect of the wireless laser communication in the future communication, especially in deep space communication. Semiconductor laser, especially the distributed feedback (DFB) laser, as the most important light source in the optical communication possesses several incomparable advantages such as high power, high efficiency, narrow spectral width and high side-mode suppression ratio. Furthermore, high electro-optical conversion semiconductor laser is also widely used in solid state lighting, energy conversion, data storage, microbial detection and spectra analysis. Therefore, fabricating high power and high efficiency DFB laser with new material and new structure is of importance in future.. ZnO is an attractive material for applications in electronics, photonics, acoustics and sensing. Its high exciton binding energy (60meV) gives ZnO an edge over other semiconductors such as GaN, which is useful in realizing electrically pumped photon emission from the excitons in ZnO. Great progress was obtained in ZnO material and ZnO-based electronic and photonic devices, such as ZnO single crystal growth, ZnO-based LED fabrication and optically pumped ZnO-based DFB laser. Despite the significant progress made, there are still a number of important issues that need to be resolved before ZnO can be transitioned to commercial use. One of the important issues is the fabrication of p-ZnO. Numerous efforts were made to improve this issue. One novel method is the fabrication of p-AlGaN instead of p-ZnO, since ZnO and GaN have similar crystal structure and similar band gap. Some inspiring improvement was obtained in the deposition of.p-GaN on ZnO. . As-mentioned about the optically pumped ZnO-based DFB laser, several papers were reported in the fabrication of thin film ZnO-based optically pumped DFB laser. However, there is still no report about the electrically pumped ZnO-based DFB laser. Here，we propose the fabrication of electrically pumped DFB laser based on single crystal n-ZnO/p-AlGaN grating. The electro-optical conversion property will be studied. Also, the growth of n-ZnO single crystal, interface structure, electron transport characteristics, electron/hole recombination mechanism in the n-ZnO/p-AlGaN structure and the hybrid photonics of the photon propagation in the n-ZnO, p-AlGaN and grating will be investigated. Furthermore, the deep etching mechanism and etching mode of p-AlGaN and single crystal n-ZnO will be carried out in order to get photonic grating with smooth vertical surface.

分布式反馈激光器是高速大容量长距离光通信和相干光通信的关键器件，也是光通信的首选光源，在固态照明、能量转换、信息存储、生物检测和光谱分析等方面有着重要的意义。ZnO作为一种重要的用于制备光电器件的半导体，到目前为止，还没有基于ZnO单晶的电泵浦DFB激光器的报导。我们首次提出基于单晶n-ZnO/p-AlGaN LED结构的谐振光子光栅制备电泵浦DFB激光器及测试其电光转换特性。研究单晶n-ZnO基板上p-AlGaN薄膜的分子束外延生长、单晶n-ZnO/p-AlGaN界面的结构、电子输运特性、空穴/电子复合发射光子机理、光子在n-ZnO、p-AlGaN和光子光栅中传输的混合光子学以及DFB激光器的阈值电流、量子效率、边模抑制比等特性。另外，我们还将研究p-AlGaN和ZnO单晶的深刻蚀机理和模式，以期获得具有平滑垂直表面的光子光栅。这将为今后的ZnO单晶和氮化物的加工提供普遍科学技术支持。

基于GaN基化合物半导体、单晶ZnO的光电子器件及其集成光电子器件，如微纳光源、谐振光子光栅、分布式反馈激光器等，是高速、高容量长距离光通信和相干光通信的关键器件，在固态照明、能量转换、信息存储、生物检测和光谱分析等方面有着重要的意义。本项目研究基于单晶n-ZnO/GaN谐振光子光栅、InGaN/ZnO-LED、分布式反馈激光器等器件的制备及光电性能。研究n-ZnO单晶的微纳加工、单晶n-ZnO基板上GaN基薄膜的分子束外延生长及其性能评价、ZnO/InGaN界面的结构、电子输运特性、空穴/电子复合发射光子机理以及光子在n-ZnO、p-AlGaN和光子光栅中传输的混合光子学。研究GaN和ZnO的深刻蚀机理和模式，以期获得具有平滑垂直表面的光子光栅。.到目前为止，进行了基于GaN和ZnO的光电器件的结构设计、理论分析与建模以及仿真分析研究。利用Comsol Multiphysics、Rsoft等软件设计和仿真分析了基于单晶n-ZnO/p-AlGaN LED结构的分布式反馈半导体激光器的光栅结构。利用TiO2纳米颗粒作为掩膜，采用硅微纳加工工艺对ZnO单晶进行刻蚀加工。获得ZnO单晶表面TiO2纳米颗粒单层密排结构和周期排列的不同直径、不同高度的ZnO纳米柱阵列。利用分子束外延设备在ZnO单晶上生长了GaN基化合物半导体微纳结构，对GaN/ZnO的微纳加工进行了探索研究并加工成InGaN/ZnO光子光栅和LED。同时还研究了SOI基GaN集成器件的设计与微纳集成制备。总之，设计和制备了几个相关的器件，TiO2/ZnO单层密排结构、单晶ZnO纳米柱阵列、InGaN/ZnO微纳结构光子光栅、InGaN/ZnO纳米柱LED、SOI基氮化镓集成角度可调滤波器、硅基氮化镓集成跟踪聚焦微镜。发表或接收期刊论文34篇，其中SCI收录论文18篇，EI收录论文5篇。申请专利10项，其中授权专利5项。