Published online by Cambridge University Press: 15 February 2011
We demonstrate strong ultraviolet (UV) (280-330nm) photoluminescence (PL) emission from multi-quantum-well (MQW) structures consisting of AlGaN active layers fabricated by metal-organic chemical-vapor-deposition (MOCVD). Si-doping is shown to be very effective in order to enhance the PL emission of AlGaN QWs. We found that the optimum values of well thickness and Si-doping concentration of AlxGal-xN/AlyGal-yN (x=0.24-0.53, y=0.11) MQW structure for efficient emission were approximately 3nm and 2×1019cm-3, respectively. In addition, the PL intensities of AlGaN, GaN and InGaN quantum well structures are compared. We have found that the PL emission at 77K from a Al0.53Ga0.47N/Al0.11Ga0.89N MQW is as strong as that of InGaN QWs.