  A model for the extraction of the charge density dependent mobility and
variable contact resistance in thin film transistors is proposed by performing
a full derivation of the current-voltage characteristics both in the linear and
saturation regime of operation. The calculated values are validated against the
ones obtained from direct experimental methods. This approach allows
unambiguous determination of both contact and channel resistance from the
analysis of the current voltage characteristics of a single device, with no
a-priori assumption on the two parameters. It solves the inconsistencies in the
commonly accepted mobility extraction methods and provides new possibilities
for the analysis of the injection and transport processes in semiconducting
materials.
