Enhanced Mobility in MoS2 Thin Film Transistors Through Kr Ion Beam-Generated Surface Defects

Abstract

Molybdenum disulfide (MoS₂) has been found to be a promising material for electronic and optoelectronic device applications due to its unique optical and electrical characteristics. However, the large-scale synthesis of MoS₂ thin films is limited by challenges in achieving reproducible and uniform device fabrication. In the present study, we utilized a sputtering technique and post-treatment by ion beam irradiation for large-scale fabrication of uniform MoS₂ thin films. The effects of the low-energy ion beam on the optical, structural, electrical transport, and morphological characteristics of the MoS₂ thin films were studied by Raman spectroscopy, atomic force microscopy (AFM), x-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy, and electrical transport analysis. Tuning the electrical and optical characteristics of few- and monolayer MoS₂ through regulation of defects provides an excellent approach for fabricating two-dimensional (2D) MoS₂ thin films for electronic device applications. Thin film transistors (TFTs) have been widely studied for driving active-matrix displays given their promising electrical characteristics including significant on/off current ratio and mobility. In the present work, we report a back-gate MoS₂ TFT fabricated by sputtering. TFTs based on MoS₂ thin films were fabricated, and the current–voltage characteristics were studied at room temperature, which confirmed that the transport behavior differed between the pristine and ion-irradiated samples. Pristine MoS₂-based TFTs displayed significant Schottky barrier effects, resulting in lower mobility than ion-irradiated samples. Our comprehensive study focuses on the fundamental transport characteristics via the metal–MoS₂interface, which represents a substantial step towards achieving highly efficient electronic devices based on 2D semiconductors.