Solution-Processed High Mobility Top-Gate N-Channel Polymer Field-Effect Transistors

Polymer field-effect transistors operated in the n-channel model with a top-gate/bottom-contact are processed using a solution method. The transistor performance depends on the gate dielectric layer. A high performance polymer transistor is achieved, with the saturated electron mobility of about 0.46 cm²/Vs, threshold voltage nearly 0 V and subthreshold sway of about 0.9 V/decade, employing a polystyrene (PS) dielectric layer. The transistor performances are further improved with increasing current and lower operation voltages by utilizing a bi-layer gate dielectric, comprising a thin PS dielectric layer adjacent to the semiconductor to minimize the density of the interface traps for obtaining a small V_T, a large μ and a poly(methyl methacrylate) (PMMA) dielectric layer with a relatively high-κ adjacent to the gate electrode for enlarging the capacitance, processed from the orthogonal solvents.