Suspended membrane GaN gratings for refractive index sensing

In this paper, we describe the fabrication and the novel procedure for back thinning the GaN layer, which leads to improved optical performance. Angular-resolved reflectance measurements are then conducted to characterize the GaN gratings and show the dependence of resonant wavelength on grating period and membrane thickness. The measured results compare well with electromagnetic modeling based on rigorous coupled wave analysis (RCWA). Altering the dielectric environment has been shown as a novel sensing mechanism, and this work opens the way to the fabrication of novel GaN resonant photonic devices for refractive index sensing applications in the visible wavelength range. (C) 2014 The Japan Society of Applied Physics