Dresden 2014 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 32: Poster: ZnO and its relatives

HL 32.7: Poster

Monday, March 31, 2014, 17:00–20:00, P2

Persistent Photoconductivity of ZnO nanowires — •Martin Dickel, Manfred Madel, Florian Huber, Bruno Amann, and Klaus Thonke — Institute of Quantum Matter / Semiconductor Physics Group, University of Ulm

A very striking characteristic of ZnO is the persistent photoconductivity (PPC). During illumination with light in the UV region, the conductivity increases, and after switching off the light, the photocurrent persists with decay times of hours. This effect is related to oxygen vacancies acting as shallow donors, which can undergo a large lattice relaxation. Also the ambient plays a important role in the PPC behaviour, especially the adsorption and desorption of oxygen from the surface. Overall this effect is still not completly understood.

In this contribution we investigate the role of temperature and different gases on the decay of the PPC. By this method, the oxygen concentration can be detected down to the lower ppm range.