Moisture induced electron traps and hysteresis in pentacene-based organic thin-film transistors

Previous work revealed that electron traps in pentacene formed in air cause hysteresis in thin-film transistor characteristics. Here, we experimentally showed that water vapor, rather than oxygen, is responsible for these hysteresis-causing trap states. Photogenerated and injected electrons are trapped at the pentacene-dielectric interface under positive gate bias, and induce extra holes, resulting in the observed extra drain current. The electron detrapping causes the decay of the extra hole population with time under negative gate bias and, therefore, that of the drain current.