Current Enhancement Phenomenon Caused by the Reversible Charge Trapping Effect Under Photoirradiation on Pentacene Field-Effect Transistors

The fundamental aspect of the photoresponse feature was investigated in pentacene field-effect transistors with respect to the current enhancement phenomenon brought about by the balanced charge effect. The photoresponsivity behaviors attributed to the induced gate bias reveal that, resulting from their substantial trapping feature, photocarriers (electrons and holes) activated in pentacene solid contribute differently to the current drivability of the device. The reversible switching behavior under photoirradiation also clearly indicates that the current enhancement predominantly comes from the balanced charge effect, compensating for reversible trapped charges (electrons) in p-type devices, as well as excited majority carriers (holes) under photoirradiation.balanced charge effect.