Regensburg 2010 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 38: ZnO and Related Semiconductors

HL 38.5: Vortrag

Mittwoch, 24. März 2010, 10:30–10:45, H17

Stable enhancement of near band edge emission of ZnO nanowires by hydrogen incorporation — •Apurba Dev¹, Raphael Niepelt², Jan Peter Richters¹, Carsten Ronning², and Tobias Voss¹ — ¹Institute of Solid State Physics, University of Bremen, Germany — ²Institute of Solid State Physics, University of Jena, Germany

ZnO nanowires have drawn considerable interest as efficient nanoscale UV light emitting device. However, due to the presence of defect states in the band gap, most of the radiative transitions take place via defect channels giving rise to a strong visible luminescence. At the same time, the near-band-edge emission is reduced. Several attempts have been made to increase the internal quantum efficiency of the UV emission by means of efficient energy transfer between surface plasmons of attached metal nanoparticles and the excitons in ZnO. In addition, passivation of the defect centers by incorporation of hydrogen impurities was also found to be a very effective way.

We performed a mild Ar plasma treatment on ZnO nanowires. The plasma-treated nanowires showed a stable and strong enhancement of the near-band-edge emission and a quenching of the deep-level emission. Photoluminescence studies at 4 K revealed a strong hydrogen donor-bound-exciton line in the plasma treated samples indicating unintentional incorporation of hydrogen. To confirm the results, hydrogen was implanted into the ZnO nanowires with a low ion energy of 600 eV and with different fluences. The observed result can be related to the passivation of deep centers by hydrogen.