Facile and Reversible Carrier-Type Manipulation of Layered MoTe₂ Toward Long-Term Stable Electronics

Flexible manipulation of the carrier transport behaviors in two-dimensional materials determines their values of practical application in logic circuits. Here, we demonstrated the carrier-type manipulation in field-effect transistors (FETs) containing α-phase molybdenum ditelluride (MoTe₂) by a rapid thermal annealing (RTA) process in dry air for hole-dominated and electron-beam (EB) treatment for electron-dominated FETs. EB treatment induced a distinct shift of the transfer curve by around 135 V compared with that of the FET-processed RTA treatment, indicating that the carrier density of the EB-treated FET was enhanced by about 1 order of magnitude. X-ray photoelectron spectroscopy analysis revealed that the atomic ratio of Te decreased from 66.4 to 60.8% in the MoTe₂ channel after EB treatment. The Fermi level is pinned near the new energy level resulting from the Te vacancies produced by the EB process, leading to the electron-dominant effect of the MoTe₂ FET. The electron-dominated MoTe₂ FET showed excellent stability for more than 700 days. Thus, we not only realized the reversible modulation of carrier-type in layered MoTe₂ FETs but also demonstrated MoTe₂ channels with desirable performance, including long-term stability.