Proton migration mechanism for the instability of organic field-effect transistors

During prolonged application of a gate bias, organic field-effect transistors show an instability involving a gradual shift of the threshold voltage toward the applied gate bias voltage. We propose a model for this instability in p-type transistors with a silicon-dioxide gate dielectric, based on hole-assisted production of protons in the accumulation layer and their subsequent migration into the gate dielectric. This model explains the much debated role of water and several other hitherto unexplained aspects of the instability of these transistors. (C) 2009 American Institute of Physics. [doi:10.1063/1.3275807]