InGaN/GaN lasers grown on SiC

Abstract

Single crystal thin films with compositions from the AlN-InN- GaN system were grown via metal-organic chemical vapor deposition (MOCVD) on single crystal 6H-SiC substrates. Blue light emitting (LED) and laser diode (LD) structures were fabricated. A conducting buffer layer was developed which uses an AlGaN buffer layer which provides a conduction path between SiC and the active device region. This conducting buffer layer was utilized in both the LEDs and the LDs. The external quantum efficiency of the LEDs was 3% at 20 mA (3.6V) with a peak emission wavelength of 430 nm. Violet and blue LDs were fabricated which consisted of an 8-well InGaN/GaN multiple quantum well (MQW) active region in a separate confinement heterostructure (SCH) design. The devices lased at room temperature under pulsed and continuous wave operation with an emission wavelength of 404-435 nm. The lowest pulsed operation threshold current density obtained for lasing under was 10.4 kA/cm 2 .