Ultraviolet Stimulated Emission From Optically Pumped AlGaN/AlGaN Multiple Quantum Wells on Pulsed Laterally Overgrown a-Plane GaN

We report the room temperature photoluminescence properties of AlGaN/AlGaN multiple quantum well (MQW) structures grown on high-quality a -plane GaN pillars oriented along the m -axis. The non-coalesced thick GaN films were laterally overgrown on r -plane sapphire at 900 °C using pulsed metalorganic chemical vapor deposition. This growth approach relies on the modulation of the nitrogen source supply while keeping the Ga precursor flow constant. Optically pumped stimulated emission (SE) from the AlGaN MQWs was demonstrated at ∼355.5 nm in the edge-emitting geometry. Unlike their c -plane counterparts, these nonpolar quantum structures exhibited SE that was predominantly polarized in the transverse magnetic mode.