Threshold voltage control of pentacene thin‐film transistor with dual‐gate structure

Abstract This paper presents a comprehensive study on threshold voltage (Vth) control of organic thin‐film transistors (OTFTs) with dual‐gate structure. The fabrication of dual‐gate pentacene OTFTs using plasma‐enhanced atomic layer deposited (PEALD) 150 nm thick Al2O3 as a bottom gate dielectric and 300 nm thick parylene or PEALD 200 nm thick Al2O3 as both a top gate dielectric and a passivation layer was investigated. The Vth of OTFT with 300 nm thick parylene as a top gate dielectric was changed from 4.7 V to 1.3 V and that with PEALD 200 nm thick Al2O3 as a top gate dielectric was changed from 1.95 V to ‐9.8 V when the voltage bias of top gate electrode was changed from ‐10 V to 10 V. The change of Vth of OTFT with dual‐gate structure was successfully investigated by an analysis of electrostatic potential.