Transition metal dichalcogenides (TMDCs) have the potential to be used in the future generation of electronic and optoelectronic devices due to their superior material properties compared to the conventional semiconductors. Although many proof of concept devices have been shown using TMDCs, the presence of large contact resistances are still a fundamental challenge to be able to realize the full potential of this material family in the functional devices. In this work, we study defect engineering by using a mild H2 plasma treatment to create defects in the WSe2 lattice. Material characterization done by X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and Kelvin probe force microscopy (KPFM) confirm a defect induced n- doping up to degenerate level that is attributed to the creation of anion (Se) vacancies. The H2 plasma treatment is adopted in the fabrication of WSe2 n-FETs. Due to n-doping at the contact regions, improvement in the device performance metrics such as ON current improvement by 20× and a near ideal subthreshold swing value of 66 mV/dec are observed. This work presents defect engineering as a reliable scheme to realize high performance electronic and optoelectronic TMDC devices.
Project end date: 09/27/16