Characteristics of Ultraviolet Laser Diodes Composed of Quaternary AlxInyGa(1-x-y)N

Ultraviolet (UV) laser diodes (LDs) whose active layers were composed of quaternary AlxInyGa(1-x-y)N were grown on epitaxially laterally overgrown GaN substrates by a metalorganic chemical vapor deposition method. We investigated the Al and In mole fractions dependence of LD characteristics in the UV region. The emission wavelength of the LDs whose active layers consisted of Al0.03In0.02Ga0.95N single quantum well (SQW) was 366.4 nm under pulsed current injection at room temperature. The lasing wavelength was the shortest ever reported for III-V nitride-based LDs. The Al0.03In0.03Ga0.94N SQW UV LDs were demonstrated under 25°C continuous-wave (cw) operation. The threshold current density and voltage of these LDs were 3.5 kA/cm2 and 4.8 V, respectively. The estimated lifetime was approximately 500 h under 25°C cw operation at an output power of 2 mW.