Ultraviolet-C AlGaN Resonant-Cavity Light-Emitting Diodes with Thermal Stability Pipe-AlGaN-Distributed Bragg Reflectors

Kuei-Ting Chen; Cheng-Jie Wang; Ying Ke; Yu-Cheng Kao; Hsiang Chen; Yung-Sen Lin; Jung Han; Chia-Feng Lin

doi:10.1021/acsomega.2c07496

Ultraviolet-C AlGaN Resonant-Cavity Light-Emitting Diodes with Thermal Stability Pipe-AlGaN-Distributed Bragg Reflectors

ACS Omega. 2023 Jan 12;8(3):3478-3483. doi: 10.1021/acsomega.2c07496. eCollection 2023 Jan 24.

Authors

Kuei-Ting Chen¹, Cheng-Jie Wang¹, Ying Ke¹, Yu-Cheng Kao¹, Hsiang Chen², Yung-Sen Lin³, Jung Han⁴, Chia-Feng Lin^{1

2}

Affiliations

¹ Department of Materials Science and Engineering, Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, Taichung 40227, Taiwan.
² Department of Applied Materials and Optoelectronic Engineering, National Chi Nan University, Puli Township, Nantou County 545301, Taiwan.
³ Department of Chemical Engineering, Feng Chia University, Seatwen, Taichung 40724, Taiwan.
⁴ Department of Electrical Engineering, Yale University, 15 Prospect Street, New Haven, Connecticut 06511, United States.

Abstract

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.