Vertical injection thin-film AlGaN/AlGaN multiple-quantum-well deep ultraviolet light-emitting diodes
Vertically injected thin-film ultraviolet light-emitting diodes operating at 325 nm and 280 nm are demonstrated. Low temperature metamorphic AlN interlayers allow crack-free growth of AlxGa1-xN with compositions of up to x=53% on GaN-on-sapphire templates. The GaN layer allows low-fluence laser-induced separation of the highly strained epi stack from the sapphire substrate with high yield. Cathode contacts are formed on etched nitrogen-face AlxGa1-xN (x=0.30 and x=0.53, for 325 and 280 nm emission, respectively) and allow vertical injection of current into the active region. Controlled roughening of the nitrogen-face AlxGa1-xN is also demonstrated through photoelectrochemical etching and results in >2.5x light extraction gain for 325 nm and 280 nm LEDs.
Zhou, L.; Epler, J. E.; Krames, M. R.; Goetz, W .; Gherasimova, M.; Ren, Z.; Kneissl, M. A. ; Johnson, N. M. Vertical injection thin-film AlGaN/AlGaN multiple-quantum-well deep ultraviolet light-emitting diodes. Applied Physics Letters. 2006 December 11; 89: 241113.