Nitride-based emitters on SiC substrates

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. The LEDs employed an AlGaN buffer layer which provides a conduction path between SIC and the active device region. The external quantum efficiency of the LEDs was 2-3% at 20 mA - 3.8V and peak emission wavelength of 430 nm. Violet and blue LDs were fabricated and consisted of an 8-well InGaN/GaN multiple quantum well (MQW) active region in a separate confinement heterostructure (SCH) design. The resulting lasers operated at room temperature using pulsed and continuous wave operation with an emission wavelength of 404-423nm. The lowest threshold current obtained for lasing was 20.2 kA/cm(2).