284-300 nm Quaternary InAlGaN-Based Deep-Ultraviolet Light-Emitting Diodes on Si(111) Substrates

We have demonstrated 280-300-nm-band quaternary InAlGaN based deep-ultraviolet (DUV) light-emitting diodes (LEDs) fabricated on Si(111) substrates, grown by low-pressure metal-organic chemical vapor deposition (LP-MOCVD). An ammonia pulsed-flow growth method was used in the initial stages of AlN growth on Si substrates in order to achieve low threading dislocation densities with thin AlN layer. We obtained single-peaked spectra from the DUV LEDs at wavelengths between 284 and 300 nm under room temperature continuous-wave (cw) operation. It is expected that low-cost and large-size DUV LEDs could become available in the near future by increasing light-extraction by removing the Si substrate. (C) 2011 The Japan Society of Applied Physics