Large area flexible electronics for analog mode continuous time applications

Conventionally, the applications of non-crystalline semiconductor based Thin Film Transistors (TFTs) are confined to large area display applications. Typically they are used in the driver circuits of pixel arrays. One of the fundamental characteristics of such TFTs is the drift in the threshold voltage VT on application of gate bias. This paper presents a novel circuit simulator based on the recursive model of VT shift and shows how the simulator can be used to explore novel analog mode continuous time applications of TFTs based on sensor actuator architectures. While operating in analog mode, VT shift causes the DC operating point of the circuit to vary. Using this circuit simulator, the concept of employing negative feedback to minimize the drain current variation in circuits made of TFTs is studied. The ideas are validated by fabricating p-type Copper phthalocyanine (CuPC) TFTs and testing the circuits.