High-gain pentacene-based inverter achieved through high and low energy ultraviolet treatments

The authors report on the fabrication of pentacene-based inverter with two p-channel thin-film transistors (TFTs) on polymer∕AlOx bilayer dielectric, which has been patterned by high energy ultraviolet (UV) (254nm) illumination. After pentacene channel growth on the dielectric, the inverter showed a high voltage gain of ∼10 under −6V supply voltage (VDD) but at a transition voltage of −1V which is too marginal to guarantee a desirable inverter operation between 0 and −6V. When low energy UV (352nm) was applied onto one of the two p TFTs, which plays as a load in the inverter circuit, the transition voltage shifted to an adequate value (−3V) because the UV changes the threshold voltage of the load TFT to be lower. The UV-treated inverter demonstrated a high voltage gain of ∼150 under a VDD of −30V.