Largely Reducing the Contact Resistance of Molybdenum Ditelluride by In Situ Potassium Modification

Abstract

Semiconducting molybdenum ditelluride (MoTe2) is widely reported owing to its favorable electronic and optoelectronic properties. The effective modulation of its electrical characteristics has garnered growing attention in regard to building high‐performance MoTe2‐based complementary devices. However, the inherent Schottky barrier (SB) in MoTe2‐based devices severely inhibits the charge‐carrier injection efficiency, leading to a high contact resistance between MoTe2 and contact metals. Here, an efficient method is presented for reducing the SB height of field‐effect transistors (FETs) based on MoTe2 by in situ potassium modification. Interestingly, the electrons transported from K continuously change the electrical characteristics of MoTe2 FET from ambipolar to n‐type with an improvement of electron mobility of over one order of magnitude. Meanwhile, the contact resistance of MoTe2 FET is significantly decreased from 11.5 to 0.4 kΩ µm. By regulating the modification region spatially, it is possible to create a complementary inverter with a high gain of ≈32 at VDD = 3 V. This research demonstrates a relatively simple method for optimizing the contact for MoTe2‐based devices and tuning the electrical properties of MoTe2 for future high‐performance complementary electronics.