期刊:IEEE Photonics Technology Letters [Institute of Electrical and Electronics Engineers] 日期:2015-09-15卷期号:27 (18): 1969-1972被引量:17
标识
DOI:10.1109/lpt.2015.2448127
摘要
AlGaN multiple quantum well lasers for optical pumping have been grown by metal-organic vapor phase epitaxy on high and low dislocation density AlN/sapphire templates. Lasers on planar templates exhibited high dislocation densities and high V-pit densities, but a smooth surface morphology leading to inefficient, but laterally very homogeneous optical emission. Lasing was not observed when optically pumped with up to 50 MW/cm2. Epitaxially laterally overgrown templates on patterned sapphire showed much lower dislocation densities, but also step bunching on the surface. This resulted in good photoluminescence efficiencies of up to 20%, but also in a higher lateral inhomogeneity of the emission. Lasers on these templates exhibited lasing at $\sim 240$ nm with low full-width at half-maximum of 1 nm and threshold power densities of 11–15 MW/cm2.