Optically pumped UV lasers grown on bulk AlN substrates

Abstract

Abstract Sub‐300 nm optically pumped ultraviolet lasers were realized on low‐defect‐density (0001) AlN substrates fabricated from single crystalline AlN boules. The Al x Ga 1– x N/Al y Ga 1– y N hetero‐structures were grown by metal‐organic vapor phase epitaxy near atmospheric pressure. The high structural quality of the pseudomorphically deposited films was confirmed by X‐ray reciprocal space mappings and time‐resolved photoluminescence (PL) studies of the multiple quantum well emission. The initial PL‐decay times for a sample emitting at 267 nm were 0.87 ns and 1.14 ns for T = 295 K and T = 14 K, respectively. Laser resonators with a length of about 1 mm were formed by cleaving the AlN crystal to obtain m‐plane mirror facets. Lasing was demonstrated for various wavelengths between 267 and 291 nm with the threshold power density as low as 126 kW/cm 2 for the shortest attempted wavelength. The laser emission was TE polarized for all emission wavelengths. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)