Ag nanowire-based electrodes for improving the output power of ultraviolet AlGaN-based light-emitting diodes

Abstract

We developed hybrid Ag nanodots (NDs)/Ag nanowires (NWs) electrodes for enhancing the light output power of near ultraviolet (NUV) AlGaN-based light-emitting diodes (LEDs). At 385 nm, 10-nm-thick ITO-only films deposited on p-GaN/sapphire gave a transmittance of 70%, whereas hybrid Ag NDs/Ag NWs film showed a transmittance of 47%. LEDs with ITO-only, Ag NDs/Ag NWs, and activated-Ag NDs/Ag NWs electrodes showed forward-bias voltages of 3.50, 3.65, and 3.57 V, respectively, at 20 mA. The LEDs with the ITO-only, Ag NDs/Ag NWs, and activated-Ag NDs/Ag NWs electrodes produced series resistances of 14.3, 15.2, and 14.5 Ω, respectively. The LEDs with the Ag NDs/Ag NWs and activated-Ag NDs/Ag NWs electrodes yielded 13.1% and 23.7% higher light output powers, respectively, at 20 mA than that produced with the ITO-only electrode. On the basis of the emission images obtained from the LEDs with 10-nm-thick ITO-only, Ag NDs/Ag NWs, and activated-Ag NDs/Ag NWs electrodes, the enhanced light output power is attributed to effective current spreading and current injection.