Field-effect transistors based on few-layered α-MoTe(2).

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) transition metal dichalcogenides (TMDs) like MoS2 and MoSe2 are extensively studied for electronic applications.
• Understanding the properties of other TMDs, such as α-molybdenum ditelluride (α-MoTe2), is crucial for expanding the range of available materials.

Purpose of the Study:

• To investigate the electronic and physical properties of few-layer α-MoTe2 field-effect transistors (FETs).
• To compare the performance of α-MoTe2 FETs with those based on MoS2 and MoSe2.

Main Methods:

• Fabrication of FETs using chemical vapor transport grown α-MoTe2 crystals mechanically exfoliated onto SiO2.
• Characterization using field-effect and Hall mobility measurements.
• Analysis of crystal properties via Raman scattering and transmission electron microscopy.

Main Results:

• α-MoTe2 FETs are hole-doped, unlike MoS2 and MoSe2.
• Observed on/off ratios exceed 10^6, with subthreshold swings around 140 mV/decade.
• Achieved field-effect and Hall mobilities approach or surpass 10 cm^2/(V·s), comparable to MoS2 and MoSe2.
• Raman scattering shows sharp modes with minimal layer-number dependence.
• Stronger spin-orbit coupling in α-MoTe2 due to Te may lead to longer decoherence times.

Conclusions:

• Few-layer α-MoTe2 exhibits promising electronic properties for FET applications.
• The hole-doping nature of α-MoTe2, contrasted with MoS2, opens possibilities for ambipolar devices and bandgap modulation when stacked.
• α-MoTe2 presents a viable alternative to MoS2 and MoSe2, with potential advantages in spin-related phenomena.