Reduction of the trap density at the organic-organic interface and resultant gate-bias dependency of the mobility in an organic thin-film transistor

We investigate the effect of the thermal treatment on the reduction of the trap density (N _it) at the organic-organic interface together with the mobility dependency to the gate-bias in an organic thin-film transistor (OTFT). The N _it between a poly(4-vinylphenol) layer and a pentacene film is found to be reduced due to the rearranged pentacene molecules during thermal treatment and the resultant mobility is obtained as high as 1.78 cm ²/V s. In addition, the mobility dependency to the gate-bias is decreased at the case of thermally-treated OTFT. It can be concluded that the N _it plays an important role on the electrical performances as well as the bias-stability.