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HL: Halbleiterphysik

HL 14: Poster I

HL 14.71: Poster

Montag, 24. März 2003, 17:00–19:30, HSZ/P2

Nonlinear transport in p-type SiGe quantum well structure containing Ge quantum dots — •K.-M. Haendel¹, R. J. Haug¹, U. Denker², O. G. Schmidt², K Eberl² und A. G. M. Jansen³ — ¹Institut für Festkörperphysik, Universität Hannover Appelstraße 2, 30167 Hannover — ²Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart — ³Grenoble High Magnetic Field Laboratory, MPIF-CNRS, Boite Postale 166, 38042 Grenoble Cedex 09, France

At deep cryogenic temperatures and high magnetic fields the conduction mechanisms of holes in a Si/SiGe-based resonant tunnelling diode with embedded self-assembled Ge quantum dots are studied. The current-voltage characteristic exhibit an abrupt vertical current increase between a low and high conductivity mode. The current in the low conductivity mode shows simply activated hopping conduction with an astonishing low activation energy. Moreover, there is evidence that a magnetic field suppresses the simply activated behavior observed in zero field and gives rise instead to variable-range hopping. The experimental results ensure that the trapping of carriers by Ge quantum dots is the responsible mechanism for the transport behavior.