Published online by Cambridge University Press: 17 March 2011
We demonstrate room temperature intense ultraviolet (UV) emission wavelength ranging 300- 340 nm from InxAlyGa1-x-yN quaternary alloys grown by metal-organic vapor-phase-epitaxy (MOVPE). We found that the UV emission is drastically enhanced by introducing several percent of In into AlGaN. We fabricated single quantum well (SQW) consisting of InxAlyGa1-x-yN quaternary well and barrier, and clearly observed In segregation of sub-micron size from a cathode luminescence (CL) images. The intensity of 320nm-band emission from InAlGaN/InAlGaN QWs were as strong as those of 410nm-band emission from InGaN based QWs, at room temperature. The temperature dependence of photoluminescence (PL) emission for InAlGaN based QWs were much improved in comparison with GaN or AlGaN based QWs. We also grew Mg-doped InxAlyGa1-x-yN quaternary, and obtained hole concentration of 3×1017cm−3 by Hall measurement for high Al content (more than 50%) InxAlyGa1-x-yN quaternary.