Dual Input AND Gate Fabricated Using a Single Channel α-sexithiophene Thin Film Field Effect Transistor

We have used a split gate field effect transistor configuration to construct a dual input logic AND gate. The device in this configuration consists of a source, a drain and two gate terminals that are positioned between the source and the drain terminals and which lie under the insulating dielectric layer. The active semiconductor used in this device was α-sexithiophene. This is a commercially available organic semiconducting molecule and can be evaporated to form uniform thin films under reduced pressure. The transistor operation was controlled by applying either 0 or -10 V to each gate electrode. When -10 volts was simultaneously applied to both gates the device was conductive. Any other combination of gate voltages rendered the device resistive. This shows that the device operates like a logic AND gate. The electric field charge mobility in this device was calculated to be ~10 -4 cm 2 /V.s and is partially attributed to the substrate topography which is not planar. The device ON/OFF ratio was ~5. These device parameters are expected to improve via the use of purified starting materials, pretreated substrates and a more planar channel topography. A significant advantage of this configuration is that AND logic devices with multiple inputs can be fabricated using a single α-sexithiophene channel with multiple gates and which in turn will lead to the fabrication of more compact electronic circuitry at reduced cost.