Regensburg 2010 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 38: ZnO and Related Semiconductors

HL 38.4: Talk

Wednesday, March 24, 2010, 10:15–10:30, H17

Light-emitting devices based on ZnO-nanowire arrays coated with p-conductive polymers — Abdelhamid Elshaer, Apurba Dev, Jan-Peter Richters, and •Tobias Voss — Institut für Festkörperphysik, Universität Bremen

Due to their large surface-to-volume ratio and high crystalline quality, ZnO nanowires are promising candidates for optoelectronic applications in the blue-UV spectral region. Especially low-temperature grown ZnO nanowires offer interesting properties for the large-scale and low-cost production of environmentally friendly solar cells and light-emitting diodes. When a p-conductive polymer is used to form a hybrid junction, stable UV emission from such a heterojunction has also been observed. We have employed a wet-chemical synthesis method to fabricate ZnO nanowire arrays on conductive glass substrates. The typical dimensions of the nanowires are about 100 nm in diameter and 2 μm in length. A thin layer of the polymer PEDOT:PSS was spin-coated onto the nanowires to fabricate compound structures acting as light emitting diodes. We studied the electroluminescence and the I-V-characteristics of the devices for different polymers and processing parameters. An additional insulating polymer layer (polystyrene) coated directly onto the nanowires was found to significantly improve the device characteristics. This is in agreement with our previous investigations of n-ZnO nanowire/p-silicon light emitting diodes where an insulating silicon dioxide layer between the n-ZnO and the p-silicon is needed to allow for tunnel injection of holes into the ZnO valence band.