高性能悬空氮化物薄膜LED器件的基础研究

This project meets the significant demand in the fields of novel optoelectronic devices and visible light communications. The basic research of freestanding nitride film LED device with high performance is carried out on the basis of nitride materials on silicon substrate. The nitride LEDs on silicon substrate emits light covering the ultraviolet to the infrared band. It also has a significant cost advantage with large size wafer. The silicon substrate and nitride epitaxial layer absorb the emitted light of LEDs, which reduces the optical performance of device. The silicon substrate and nitride epitaxial layer also increase the junction capacitance and equivalent resistance of LEDs, which limits the modulation bandwidth of the device and hinders its application in the field of visible light communication. This project focuses on peeling off the silicon substrate and thinning the freestanding nitride film from backside. The freestanding nitride film LEDs would be obtained to realize the high performance with low drive voltage, higher optical efficiency, high response speed and high modulation bandwidth. The nitride micro actuator is integrated with LEDs to obtain the MEMS tunable LED light source. The direction of emitted light is controlled by the light source. The optical device is integrated with LEDs to achieve the interaction between optical device and emitted light. FWHM, the frequency response characteristic and the transmission form of LEDs are regulated to obtain the integrated LED optical system. The application of lighting, display and visible light communications is expanded.

本课题面向新型光电子器件和可见光无线通信领域的重大需求，基于硅衬底氮化物材料体系,开展高性能悬空氮化物薄膜LED器件基础研究。硅衬底氮化物LED器件能产生覆盖紫外至红外波段的光，且在大尺寸晶片上具有明显成本优势。然而硅衬底和氮化物外延层对LED器件出射光吸收大，影响器件光学性能。硅衬底和外延层也会增大器件结电容和等效电阻，限制LED器件调制带宽，阻碍其在可见光通信领域的应用。针对上述问题，本课题重点发展硅衬底剥离和悬空氮化物薄膜背后减薄技术，获得具有低驱动电压、高出光效率、高响应速度、高调制带宽的悬空氮化物薄膜LED器件。在此基础上将氮化物微驱动器与LED器件集成获得微机电可调LED光源，操纵出射光方向；探索将光子器件与LED器件集成，利用光子器件与出射光的交互作用，对其半高宽、频率响应特性和传输形式进行调控，获得可调可控的集成LED光学系统，拓展其在照明显示，特别是可见光通信领域的应用。

本课题面向新型光电子器件和可见光无线通信领域的重大需求，基于硅衬底氮化物材料体系，开展高性能悬空氮化物薄膜LED器件基础研究。硅衬底氮化物LED器件能产生覆盖紫外至红外波段的光，且在大尺寸晶片上具有明显成本优势。然而硅衬底和氮化物外延层对LED器件出射光吸收大，影响器件光学性能。硅衬底和外延层也会增大器件结电容和等效电阻，限制LED器件调制带宽，阻碍其在可见光通信领域的应用。针对上述问题，本课题结合硅衬底剥离技术和悬空氮化物薄膜背后减薄技术，实现了优良光电性能的悬空氮化物薄膜LED器件；通过控制背后刻蚀技术，制备了具有不同薄膜厚度的悬空LED器件，并对其光电性能进行了仿真分析和测试表征；制备了基于硅衬底LED晶片的悬空多功能光电器件，在单片集成式光电器件上实现了LED光源、平面光波导和光电探测器多种功能；面向可见光通信，开发了集成悬空氮化物薄膜和波导的集成光子芯片，实现了高速可见光通信。