Dresden 2011 – scientific programme

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DS: Fachverband Dünne Schichten

DS 61: Thermoelectric Materials, Thin Films, and Nanostructures III (Focused Session -- Organisers: Nielsch, Rastelli, Balke)

DS 61.2: Talk

Friday, March 18, 2011, 16:15–16:30, GER 37

Model calculations of the thermoelectric transport across a back to back Schottky barrier — •Michael Bachmann, Michael Czerner, and Christian Heiliger — Physikalisches Institut, Justus Liebig University Giessen, D-35392, Germany

We present results of electronic transport calculations across a back to back Schottky barrier [1]. The basic idea of the back to back Schottky barrier is the assumption of additional electronic states in the band gap at grain boundaries. For an n-type semiconductor these states can be filled by electrons from donor levels. This will lead to a negative space charge region directly at the grain boundary and to positive space charge regions on both sides of the grain boundary. We can change the potential profile by varying the total net charge trapped at the grain boundary. For a given total net charge the potential profile is a function of the donor concentrations. The potential profile is obtained by solving the Poisson equation with a finite difference method on a discrete net. From the potential profile we calculate the transmission function using non equilibrium Greens function formalism considering one parabolic band. For the temperature dependency of the chemical potential we consider one Gaussian shaped donor level and impose charge neutrality. The thermoelectric parameters are calculated using the momentum representation of the transmission function weighted with the energy derivative of the Fermi function [2].

[1] C R M Grovenor J.Phys. C: Solid State Phys. 184079 (1985)

[2] H. Fritzsche Solid State Com. Vol. 9 pp. 1813-1815 (1971)