Device operation mechanism of field-effect transistors with high mobility donor-acceptor polymer semiconductors

The mechanism of high field-effect mobility observed recently in transistors with donor-acceptor alternating polymers was experimentally and numerically examined. It was revealed that the trapped electrons injected from the drain electrode into the lowest unoccupied molecular orbital states of semiconductor polymers cause a deviation from the ideal transistor curve and result in an overestimation of hole mobilities. The field-effect mobility of 19 cm(2)/Vs was deduced by the standard formula for extracting mobility in the saturation regime after electron trapping, while the true mobility of 0.84 cm(2)/Vs was extracted before electron trapping.