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HL: Halbleiterphysik

HL 7: Poster I

HL 7.48: Poster

Monday, March 26, 2001, 10:30–19:00, Rang S\ 3

C-V characteristics of open quantum nanostructures — •Paul N. Racec^1,2 and Ulrich Wulf¹ — ¹Technische Universitaet Cottbus, Fakultaet 1, 03013 Cottbus, Germany Postfach 101344, — ²National Institute for R&D of Materials Physics, P.O.B MG-7, 76900 Bucharest, Romania

We consider a semiconductor device composed of a small quantum structure as the active device region and two classical environments constituting the source- and the drain contact. The electronic wavefunctions are scattering waves emitted from the source contact and the Coulomb interaction is taken in the Hartree approximation. As an example we consider the formation of field induced 2DEG in front of a blocking barrier. Experimentally, this formation is accompanied with a jump in the capacitance. Our calculations show that this jump is due to quasi-bound resonances in the open system. They undergo a transition to the known quantum levels of the bound system, which for stronger fields can be described by Fang-Howard variational wave functions. The influence of the coupling between contacts and the quantum system on the C-V is also analyzed.