Regensburg 2004 – scientific programme

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HL: Halbleiterphysik

HL 44: Poster II

HL 44.14: Poster

Thursday, March 11, 2004, 16:30–19:00, Poster A

Magnetoresistance of Schottky Diodes — •M. Ziese — Division of Superconductivity and Magnetism, University of Leipzig, Linnéstrasse 5, 04103 Leipzig.

The magnetoresistance of commercial Schottky diodes was investigated. The current-voltage characteristics of passivated Si-Schottky contacts obtained from various suppliers were measured in an applied magnetic field up to 8 T at temperatures between 5 K and 300 K. All samples studied showed similar behaviour. Down to 80 K the current-voltage characteristics can be understood within thermionic emission theory, between 80 K and 50 K a crossover to tunnelling is seen. Below 50 K the charge carriers freeze in and an appreciable series resistance develops. Below 30 K a second nonlinear conduction process appears at high voltages. This process is strongly magnetic field dependent and at 5 K a significant shift of the current-voltage characteristics in an applied field is observed. The magnetoresistance reaches +40% in 5 T at 10 K, decays strongly with increasing temperature and vanishes above 30 K; it depends on the relative direction between current and magnetic field. These findings are discussed within a model of nonlinear current transport.