White electroluminescence from a hybrid polymer-GaN:Mg nanocrystals device

A magnesium-doped gallium nitride nanocrystal (GaN:Mg NC)-based electroluminescence (EL) device is reported with a hybrid organic/inorganic structure of indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene) doped with poly (styrenesulphonic acid) (PEDOT:PSS)/GaN:Mg NCs/Ca/Al. The conducting polymer, PEDOT:PSS layer, was used to enhance hole injection from the ITO electrode. Current-voltage characteristics of the GaN:Mg nanocrystal-based EL device show a diodelike behavior. White electroluminescence was observed from the device and a voltage-dependent phenomenon of EL emission spectra was found and investigated. A good correlation between the EL and photoluminescence emission peaks suggests that electron-hole recombination indeed occur in the GaN:Mg nanocrystals layer.