Electroluminescence from ZnO nanowire/polymer composite p-n junction

The characteristics of a hybrid p-n junction consisting of the hole-conducting polymer poly(3,4-ethylene-dioxythiophene)-poly(styrene-sulfonate) (PEDOT/PSS) and n-ZnO nanorods grown on an n-GaN layer on sapphire are reported. Spin coating of polystyrene was used to electrically isolate neighboring nanorods and a top layer of transparent conducting indium tin oxide (ITO) was used to contact the PEDOT/PSS. Multiple peaks are observed in the electroluminescence spectrum from the structure under forward bias, including ZnO band edge emission at ∼383nm as well as peaks at 430, 640, and 748nm. The threshold bias for UV light emission was <3V, corresponding to a current density of 6.08Acm−2 through the PEDOT/PSS at 3V.