Conductance simulation in an a-Si:H thin-film transistor with Schottky barriers

It is shown by numerical simulation that the drain-source Schottky contacts substantially control the conductance of a thin-film transistor in the above-barrier region. At a barrier height in excess of 0.75 eV, the effect of crowding manifests itself; this effect is caused by an increase in electric field at the edge of the source electrode as the pulling voltage is increased, which brings about a local lowering of the barrier and an increase in the current through the reverse-biased Schottky barrier. The effective mobility in the thin-film transistor is controlled by the film and is independent of the barrier height.