Chemical Physics Letters, Vol.681, 36-39, 2017
Understanding mobility degeneration mechanism in organic thin-film transistors (OTFT)
Mobility degradation at high gate bias is often observed in organic thin film transistors. We propose a mechanism for this confusing phenomenon, based on the percolation theory with the presence of disordered energy landscape with an exponential density of states. Within a simple model we show how the surface states at insulator/organic interface trap a portion of channel carriers, and result in decrease of mobility as well as source/drain current with gate voltage. Depending on the competition between the carrier accumulation and surface trapping effect, two different carrier density dependences of mobility are obtained, in excellent agreement with experiment data. (C) 2017 Elsevier B.V. All rights reserved.