Vertically oriented GaN-based air-gap distributed Bragg reflector structure fabricated using band-gap-selective photoelectrochemical etching

Abstract

A three-period vertically oriented GaN-based air-gap distributed Bragg reflector structure was fabricated using band-gap-selective photoelectrochemical (PEC) etching. The epitaxial structure consisted of an Al0.08Ga0.92N∕(In0.04Ga0.96N∕In0.07Ga0.93N) superlattice structure, wherein the InGaN layers served as sacrificial layers during PEC etching. Microreflectance measurements yielded an average enhancement in the reflected signal of ∼12-fold over the wavelength range of 550–650 nm, when compared with the signal from a dry-etched GaN surface.