Oxygen plasma induced improvement of contact resistance and mobility of tellurium field-effect transistor

Abstract

Two-dimensional tellurium (Te) has been intensely studied in recent years due to its outstanding electrical properties and excellent air stability. Simple and effective contact engineering is highly desirable to further improve its device performance. In this work, we demonstrate a simple strategy to largely improve the metal–Te contact quality by forming an ultrathin tellurium oxide layer in the contact region via O2 plasma treatment. The surface oxide doped the underlying Te layers degenerately due to charge transfer, establishing an Ohmic contact between Pd electrode and Te with negative Schottky barrier under flatband condition. This enables Te field-effect transistor to achieve outstanding electronic performance, including a record-low contact resistance of ∼0.16 kΩ·μm and a high field-effect mobility of ∼1015 cm2V−1s−1 (∼3002 cm2V−1s−1) at room temperature (low temperature). The simplicity and CMOS compatibility of O2 plasma treatment make it a promising candidate for applications in Te-based large-scale integrated circuits.