Guided-Mode Resonances in GaN Membrane Grating

This paper proposes guided-mode resonant GaN grating that are implemented on a GaN-on-silicon wafer structure. Numerical simulations based on rigorous coupled wave analysis (RCWA) are performed to model multiple resonances in thick GaN membranes. Back wafer etching of freestanding GaN membranes is used as a tuning mechanism to manipulate the optical performance in the visible wavelength range. Angular resolved micro reflectance measurements are conducted to characterize the fabricated GaN gratings and show the dependence of guided-mode resonances on the filling factor of the gratings, the membrane thickness, and the polarization of incident beam. The experimental results agree well with numerical simulations. This paper opens the way to fabricate guided-mode resonant GaN grating for many diverse applications.