Dynamic bias stress current instability caused by charge trapping and detrapping in pentacene thin film transistors

Abstract

The current instability in pentacene organic thin film transistors (OTFTs) under dynamic bias stress was investigated. Current instability is strongly influenced by pulse duty ratio and pulse on-period and off-period voltages, but is independent of pulse frequency. A stable on-current without current instability was achieved by controlling the pulse duty ratio and pulse voltage. On the basis of the experimental results, a reversible transition model of dynamic charge trapping and detrapping in pentacene OTFTs is proposed, and trapping and detrapping time constants were estimated.