Light emission enhancement of GaN-based photonic crystal with ultraviolet AlN/AlGaN distributed Bragg reflector

In this study, we demonstrated two-dimensional (2-D) photonic crystal band-edge coupling operation in the ultraviolet wavelength range. The light extraction enhancement was obtained from the photonic crystal structure with an ultraviolet AlN/AlGaN distributed Bragg reflector (UVDBR). The DBR provides a high reflectivity of 85%with15-nmstopbandwidth.Afivefold enhance- ment in photoluminescence emission was also achieved compared with the emission from the unpatterned area on the same sample at 374 nm wavelength. We also study the photonic crystal band- edge coupling with finite-difference time-domain and plane-wave expansion methods.