Vertical-cavity, room-temperature stimulated emission from photopumped GaN films deposited over sapphire substrates using low-pressure metalorganic chemical vapor deposition

We report the first observation of near-UV vertical-cavity stimulated emission from a photopumped GaN epilayer at room temperature. The epilayer was deposited over AIN-coated basal plane sapphire substrate using low-pressure metalorganic chemical vapor deposition. Epitaxy quality of a 1.5-μm-thick GaN layer was high enough to achieve stimulated emission at room temperature. The observed near-UV optical emission power was a nonlinear function of the pump power density. At threshold power density, we also observed line narrowing and a shift of the peak UV emission towards longer wavelengths. Data comparing the UV emission for the vertical-cavity and the edge emission geometry are also presented.