Chen Kuei-Ting, Wang Cheng-Jie, Ke Ying, Kao Yu-Cheng, Chen Hsiang, Lin Yung-Sen, Han Jung, Lin Chia-Feng
Department of Materials Science and Engineering, Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, Taichung 40227, Taiwan.
Department of Applied Materials and Optoelectronic Engineering, National Chi Nan University, Puli Township, Nantou County 545301, Taiwan.
ACS Omega. 2023 Jan 12;8(3):3478-3483. doi: 10.1021/acsomega.2c07496. eCollection 2023 Jan 24.
Ultraviolet-C AlGaN resonant-cavity light-emitting diodes with top and bottom pipe-AlGaN-distributed Bragg reflectors (DBRs) have been demonstrated. For the top/bottom DBR structures, 20 pairs of n-AlGaN:Si/n-AlGaN:Si stack structures were transformed into the pipe-AlGaN:Si/n-AlGaN:Si DBRs through a doping-selective electrochemical wet etching process. The reflectivity of the pipe-AlGaN DBR structure was measured as 90% at 276.7 nm with a 20.9 nm flat stopband width. The anisotropic optical properties of the pipe-AlGaN DBR structure had been analyzed through the polarization-dependent reflectance spectra. For temperature-dependent reflectance spectra, the central wavelengths were slightly redshifted from 275 nm (100 K) to 281 nm (600 K) due to thermal expansion, refractive index increase, and partial strain release phenomena in the pipe-DBR structure. High photoluminescence emission intensity and line-width reducing phenomena were observed at 10 K in the UVC-LED with the resonant-cavity structure, which has potential for high-efficiency UV-C light source applications.
已展示出具有顶部和底部管状 AlGaN 分布布拉格反射器（DBR）的紫外 C 型氮化铝镓谐振腔发光二极管。对于顶部/底部 DBR 结构，通过掺杂选择性电化学湿法蚀刻工艺，将 20 对 n-AlGaN:Si/n-AlGaN:Si 堆叠结构转变为管状 AlGaN:Si/n-AlGaN:Si DBR。在 276.7 nm 处测得管状 AlGaN DBR 结构的反射率为 90%，平坦阻带宽度为 20.9 nm。通过偏振相关反射光谱分析了管状 AlGaN DBR 结构的各向异性光学特性。对于温度相关反射光谱，由于管状 DBR 结构中的热膨胀、折射率增加和部分应变释放现象，中心波长从 275 nm（100 K）到 281 nm（600 K）略有红移。在具有谐振腔结构的 UVC 发光二极管中，在 10 K 时观察到高光致发光发射强度和线宽减小现象，这使其有潜力用于高效紫外 C 光源应用。
