365 nm Ultraviolet Laser Diodes Composed of Quaternary AlInGaN Alloy

Abstract

Ultraviolet (UV) laser diodes (LDs), whose active layer were quaternary AlxInyGa1-x-yN single-quantum well structure, were grown on epitaxial lateral overgrown GaN substrates by a metalorganic chemical vapor deposition method. We investigated the lasing wavelength dependence of UV LDs on the threshold current density. As a result, we succeeded in fabricating 365 nm UV LDs which are useful for various industrial uses because their wavelength is similar to that of the i-line of high-pressure mercury vapor lamps. The threshold current and voltage of the 365 nm UV LD under continuous wave (cw) operation at 25°C were 50 mA and 4.8 V, respectively. The estimated lifetime of the 365 nm UV LDs was approximately 2000 h at an output power of 3 mW under cw operation at 30°C. The shortest lasing wavelength was achieved at 354.7 nm under pulse current injection at 25°C.