Molybdenum disulfide field-effect transistors with enhanced charge-injection by inserting ultrathin pentacene layer under source/drain electrodes

Abstract

We report a method to improve charge-injection properties of molybdenum disulfide (MoS2)-based field-effect transistors (FETs) by introducing ultrathin pentacene film as the buffer layer under the source/drain electrodes. Compared with conventional devices with metal-only electrodes, the electrical characteristics of MoS2 FETs with the organic buffer layer exhibit a ten-fold enhancement in on-state current and a four-fold increase in field-effect mobility. These improvements are attributed to the introduction of organic buffer layer with hole-type that result in optimized contact properties. The Schottky barrier height is lowered by approximately 0.3 eV for the electron-injection in MoS2 FETs. Furthermore, electrons in metal and MoS2 could be effectively attracted to the surfaces by holes in pentacene film resulting in a tunnelling probability, which is responsible for the improved charge-injection. Current studies will be helpful in the development of high performance MoS2 optoelectrical devices.