Crack-free highly reflective AlInN∕AlGaN Bragg mirrors for UV applications

Abstract

We report the growth of highly reflective distributed Bragg reflectors (DBRs) in the UV region using the Al0.85In0.15N∕Al0.2Ga0.8N lattice-matched system. The DBRs were deposited on nearly strain-free Al0.2Ga0.8N templates to avoid strain-induced structural degradations. The appearance of cracks was then completely suppressed. The DBRs exhibit a reflectivity higher than 99% at a wavelength as short as ∼340nm and a stop band width of 215meV (20nm).