Tunneling transport in devices with semiconducting leads

Emil Prodan, Amy LeVee

Published 2009-07-27, updated 2010-02-08Version 2

This paper extends the modern theory of tunneling transport to finite temperatures. The extension enables applications to molecular electronic devices connected to semiconducting leads. The paper presents an application of the theory to molecular devices made of alkyl chains connected to silicon nano-wires, mapping their transport characteristics as functions of temperature and alkyl chain's length. Based on these calculations and on the analytic theory, it is found that the tunneling decay constant is determined not by the Fermi level, but by the edge of the valence or conductance band, whichever is closer to the Fermi level. Further insight is provided by mapping the evanescent transport channels of the alkyl chains and few other physical quantities appearing in the analytic formula for conductance. A good qualitative agreement with the experimental data is obtained.