Ultraviolet-enhanced device properties in pentacene-based thin-film transistors

The authors report on the ultraviolet (UV)-enhanced device properties in pentacene-based thin-film transistors (TFTs). Pentacene TFTs showed a degraded mobility and lowered saturation current after illumination by a high energy UV with 254 nm wavelength. However, under 364 nm UV these devices surprisingly displayed enhanced saturation current and also showed threshold voltage shift toward lower values, maintaining their mobilities. The saturation current increase and threshold voltage shift were further related to the negative fixed charges excessively formed at the pentacene/dielectric interface by the low energy UV. The authors thus conclude that a low energy UV could rather enhance the pentacene TFT performances and also control the threshold voltage of the device.