OPTICALLY PUMPED GAN AL0.1GA0.9N DOUBLE-HETEROSTRUCTURE ULTRAVIOLET-LASER/

Molecular-beam epitaxy was used to grow a 100 nm Al0.1Ga0.9N/100 nm Ga N/500 nm Al0.1Ga0.9N double heterostructure on a 10-mu m-thick GaN buf fer layer grown with hydride vapor phase epitaxy on (0001) sapphire. L asing from the 100 nm GaN active layer has been obtained at similar to 359 nm at liquid-nitrogen temperature (77 K) and at similar to 365 nm at room temperature (295 K), using transverse optical pumping at 337. 1 nm with a 600 ps transversely excited atmospheric pressure pulsed ni trogen laser. Threshold pump fluences were measured to be 0.3 and 0.5 mJ/cm(2) at 77 and 295 K, respectively, for a laser with 65 mu m cavit y length. In a laser of 23 mu m cavity length, longitudinal cavity mod es were observed with 0.56 nm spacing, corresponding to a group refrac tive index of 5.0 at the lasing wavelength. (C) 1996 American Institut e of Physics.