Advances in InAlGaN laser diode technology toward the development of UV optical sources (Invited paper)
We report on ultraviolet (UV) InGaN and GaN multiple quantum well (MQW) laser diodes grown on c-plane sapphire substrates by metal organic chemical vapor deposition. By reducing the indium content in the InGaN/InAlGaN MQW, we have systematically pushed the room-temperature laser emission to a record low wavelength of 363.2nm. Pulsed threshold current densities around 5 kA/cm2 have been achieved for laser diodes with emission wavelength between 368 nm and 378 nm. Light output powers greater than 400mW under pulsed current-injection conditions (pulse duration 500 ns, repetition frequency 1 kHz) and differential quantum efficiencies of 4.8% have been achieved. We also demonstrate room-temperature continuous-wave operation of ridge-waveguide devices with threshold currents of 85 mA for an emission wavelength of 377.8 nm and output power of more than 3 mW.
Kneissl, M. A. ; Treat, D. W. ; Teepe, M. R. ; Miyashita, N. ; Johnson, N. M. Advances in InAlGaN laser diode technology toward the development of UV optical sources (Invited paper). Photonics West 2003: Novel In-Plane Semiconductor Lasers II; 2003 January 25-31; San Jose, CA. Bellingham, WA: SPIE; 2003; SPIE Proceedings vol. 4995: 103-107.