Light emissions from organic crystal field-effect transistors with dual-gate contacts

Abstract

We incorporated a dual-gate structure into organic crystal field-effect transistors (OCFETs). An organic semiconductor crystal was laminated on the comb-shaped interdigitated Cr/Au source and drain that were preliminarily deposited on SiO2 (used as a bottom-gate insulator) covering Si (a bottom-gate contact). On top of the crystal, we successively formed a parylene top-gate insulator and an Au top-gate contact. High hole mobilities were observed by applying voltages to both gate contacts and by applying a certain voltage to the top-gate contact with the bottom-gate contact floated. The drain currents of dual-gate devices are larger than those of single-gate devices with only the bottom-gate contact. Dual-gate OCFETs produce light emissions with the application of alternating-current (AC) voltages to both gate contacts. The dual-gate OCFETs require gate voltages lower than those of single-gate devices. These results indicate that dual-gate structures are useful for realizing high hole mobilities and current-injected light emissions by facilitating carrier injections into the OCFETs.