Dresden 2011 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 26: Interfaces and Surfaces

HL 26.3: Talk

Monday, March 14, 2011, 16:30–16:45, POT 06

Nanowire-metal hybrid structures: the influence of the deposition technique on the optical properties — •Apurba Dev, Jan-Peter Richters, and Tobias Voss — Institute of Solid State Physics. University of Bremen. 28359 Bremen

ZnO nanowires (NWs) have drawn widespread attention for their potential use in many optical devices. Recently, surface plasmon resonances of metal nanoparticles (NPs) have been used to increase the quantum efficiency of near-band-edge (NBE) spontaneous emission of these nanowires. However, we observed that the metal NPs deposition process itself significantly influences the optical properties. We investigated the time-integrated and time-resolved photoluminescence (PL) properties of ZnO NWs coated with Au, Ag and Pt NPs which were deposited by DC sputtering in Ar plasma. The influence of the sputtering process was determined by performing the same sputtering treatment while shielding the sample to avoid metal deposition. A strong enhancement of the NBE emission and a quenching of the deep-level emission were observed in all cases. Time-resolved spectroscopy showed a reduction of the radiative lifetime in all samples irrespective of size and kind of metal NPs. PL studies at 4 K revealed a strong hydrogen-donor-bound-exciton line indicating unintentional incorporation of hydrogen. The results can be explained by considering the passivation of deep centers by hydrogen and the introduction of a large amount of hydrogen donors.