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HL: Halbleiterphysik

HL 9: Poster I

HL 9.6: Poster

Montag, 27. März 2006, 15:15–17:45, P3

Spatial fluctuations of the local potential in Silicon doped GaAs — •K. Teichmann¹, S. Loth¹, M. Wenderoth¹, R. G. Ulbrich¹, and U. Kretzer² — ¹Universität Göttingen, IV. Physikalisches Institut, Germany — ²Freiberger Compound Materials GmbH, Freiberg, Germany

We investigated highly Silicon doped GaAs (10⁺¹⁹ cm⁻³). Silicon is typically incorporated as a shallow donor, and is known to show strong autocompensation at high doping concentrations [1]. In our measurement we used UHV scanning tunneling microscopy at 8K. We prepared our sample as {110} cleavage plane. In particular we investigated distribution of dopants. In addition constant current topographies reveal a large amount of dopant induced defects. Both are not statistically distributed and show significant clustering on a length scale of several nanometers. By scanning the same region of the sample with different voltages (multibias spectroscopy) and by performing dI/dz spectroscopy we studied the correlation between the local dopant distribution and the electrostatic potential (φ_el.stat.(x,y)) as well as the local apparent barrier height.

[1] C. Domke et al., Phys. Rev. B 54, 10288 (1996).