Eur. Phys. J. B 72, 183-191 (2009)
https://doi.org/10.1140/epjb/e2009-00348-3

Analytical study of non-linear transport across a semiconductor-metal junction

Resonances, surface states, and non-linear transport

Department of Physics and Center of Physics, University of Minho, 4710-057 Braga, Portugal

Corresponding author: ^a peres@fisica.uminho.pt

Received: 28 April 2009
Revised: 5 June 2009
Published online: 17 October 2009

Abstract

In this paper we study analytically a one-dimensional model for a semiconductor-metal junction. We study the formation of Tamm states and how they evolve when the semi-infinite semiconductor and metal are coupled together. The non-linear current, as a function of the bias voltage, is studied using the non-equilibrium Green's function method and the density matrix of the interface is given. The electronic occupation of the sites defining the interface has strong non-linearities as a function of the bias voltage due to strong resonances present in the Green's functions of the junction sites. The surface Green's function is computed analytically by solving a quadratic matrix equation, which does not require adding a small imaginary constant to the energy. The wave function for the surface states is given.