Free-standing, optically pumped, GaN/InGaN microdisk lasers fabricated by photoelectrochemical etching

GaN-based, mushroom-shaped microdisk lasers were fabricated using band-gap selective photoelectrochemical etching. The optically pumped microdisks had well-defined, distinct modes at excitation powers ranging from about 8 to 16 W/cm(2). Modal linewidths of 0.09 nm were reported, which was near the resolution of the measurement equipment. Quality factors for the microdisks were >4600. The observed lasing threshold was 12.1 W/cm(2). At higher excitation powers, heating effects and degradation were observed in the optical response of the microdisks. (C) 2004 American Institute of Physics.