Graphene Oxide as a Dielectric and Charge Trap Element in Pentacene-Based Organic Thin-Film Transistors for Nonvolatile Memory.

Abstract

In this report, the dielectric nature of graphene oxide (GO) was exploited for the successful implementation of low-power pentacene thin-film transistors suitable for nonvolatile memory applications. Two different types of devices were fabricated on indium tin oxide-coated glass substrates with two different metals, viz., gold and aluminum, as the source and drain contacts. The performance of the devices was analyzed from their field-effect characteristics. Both the devices showed dominant p-type charge transport behavior. The breakdown electric field was determined to be 1.02 × 108 V/m. The current transport mechanism was explained from the output characteristics using the Fowler–Nordheim tunneling theory. Capacitance–voltage (C–V) measurements have been employed to determine the value of the oxide capacitance and to examine the memory effect. The hysteresis behavior observed from the C–V characteristics show the suitability of the device for memory applications with a low operating voltage of 3 V. The charge trapping behavior of GO was explained by the energy band diagram. Frequency-dependent C–V measurements in the range 100 kHz to 1 MHz were also performed to account for the memory window obtained in the devices. The charge retention and endurance characteristics were evaluated under a constant voltage stress to check the reliability of device operation.