Enormous enhancement in electrical performance of few-layered MoTe₂ due to Schottky barrier reduction induced by ultraviolet ozone treatment

Doping can improve the band alignment at the metal-semiconductor interface to modify the corresponding Schottky barrier, which is crucial for the realization of high-performance logic components. Here, we systematically investigated a convenient and effective method, ultraviolet ozone treatment, for p-type doping of MoTe₂ field-effect transistors to enormously enhance the corresponding electrical performance. The resulted hole concentration and mobility are near 100 times enhanced to be ~ 1.0 × 10¹³ cm^-2 and 101.4 cm²/(V·s), respectively, and the conductivity is improved by 5 orders of magnitude. These values are comparable to the highest ones ever obtained via annealing doping or non-lithographic fabrication methods at room temperature. Compared with the pristine one, the photoresponsivity (522 mA/W) is enhanced approximately 100 times. Such excellent performances can be attributed to the sharply reduced Schottky barrier because of the surface charge transfer from MoTe₂ to MoO_x (x < 3), as proved by photoemission spectroscopy. Additionally, the p-doped devices exhibit excellent stability in ambient air. Our findings show significant potential in future nanoelectronic and optoelectronic applications.