Organic-Single-Crystal Vertical Field-Effect Transistors and Phototransistors.

Abstract

Organic vertical field-effect transistors (VFETs) have attracted significant attention over the past years due to their unique characteristics of high output currents, low operation voltages, high working frequency, and promising high-density integration for circuits. However, most currently reported VFETs demonstrate poor performance, e.g., with low on/off ratio and current density. Here, the first organic-single-crystal vertical field-effect transistors (SC-VFETs) and phototransistors are constructed from 2,6-diphenyl anthracene (DPA) through a modified method. The devices exhibit high on/off ratio of 10⁶ and a high current density of 100 mA cm^-2 under a small voltage of -5 V, which are proved to be one of the best performances for organic VFETs. Furthermore, superior photoresponse performance with photoresponsivity of 110 A W^-1 and detectivity of 10¹³ Jones is obtained under light illumination for vertical phototransistors. These results confirm the control of the intrinsic Schottky barrier height at the graphene-DPA junction along with good interfacial contact effectively suppressing the dark current to realize a large on/off ratio and high light detectivity. This vertical integration of graphene with organic single crystals via simple, effective fabrication processes opens up new opportunities to realize high-performance integrated organic vertical electronic and optoelectronic devices.