Polymer electret-based organic field-effect transistor memory with a solution-processable bilayer (PαMS/ cross-linked PVP) gate dielectric

Abstract

Pentacene based organic field-effect transistors (OFETs) were fabricated, with both cross-linked poly vinyl phenol (CL-PVP) and a bilayer of poly(α-methylstyrene) (PαMS)/ CL-PVP as gate dielectric. The PαMS layer decreases the surface energy of the gate dielectric and increases the hydrophobic nature, which leads to favorable growth of pentacene and the corresponding field-effect mobility, though at a higher gate voltage span, increases three times compared to that of the device with only CL-PVP as the gate dielectric. OFET with bilayer polymer gate dielectric exhibited non-volatile memory behavior with an on-off ratio 103, retention time >103 s and a large memory window of −25 V. The memory effect observed in the device was due to the charge trapping in the PαMS layer, with CL-PVP acting as a blocking dielectric. Our studies indicate that the bilayer dielectric, comprising of solution-processable PαMS/CL-PVP is a good choice for obtaining non-volatile electret memory on an OFET platform.