Experimental and theoretical insights into electronic properties of oxygen-doped MoTe2 field effect transistor

Abstract

Modulating the electrical and photo-electrical properties is essential to enlighten the potential application in the case of field-effect transistors and other electronic devices. Molybdenum ditelluride (MoTe2), which has a limited energy gap and shows spin-orbit coupling, has piqued curiosity among two-dimensional (2D) transition metal dichalcogenides (TMDCs) and has appeared as a significant material with innovative electronic applications. In this work, we have reported the electrical modulation of multilayer MoTe2-FETs by gas doping under deep ultra-violet (DUV) light. After DUV treatment, the device characteristics were also investigated with oxygen doping. A shift in threshold voltage was observed from negative to positive back-gate voltage (Vbg), revealing a p-type doping effect. This doping effect is further confirmed through the Raman peaks, A1g and E12g were shifted towards higher wavenumbers. For pristine to 30-min doping intervals, the current ON/OFF ratio increased from 104 to 106 and the mobility of the device is enhanced from 22.36 cm2/V.s to 102.43 cm2/V.s. In addition, we used density functional theory (DFT) to investigate the impact of oxygen doping on the electrical and optical properties of MoTe2. The electronic bandgap was determined to be 0.8 eV, which can be a promising material for lower energy devices. The oxygen-doped MoTe2-based field-effect transistors are predicted to be a promising contender for low and high-temperature applications based on the highly intense peak of absorption spectra in the ultra-violet and visible regions of electromagnetic spectra.