Metal contacts in thin-film transistors

The effects of metal contacts on the electrical characteristics in thin-film transistors are discussed. It is found that the effects of these contacts are twofold. First, a constant potential that can range from zero to some volts (half the bandgap) is added to the entire channel. Second, a residual barrier is formed with a height that depends on the bias, and is in the order of tens of meV when a current is present. It is shown that these predicted effects are in agreement with experimental observations.