High field-effect performance and intrinsic scattering in the two-dimensional MoS2 semiconductors

The mobility of MoS2 nanosheets plays an important role in the application of nanoelectronics. The twodimensional (2D) MoS2 semiconductors have been investigated while the reported mobility varies enormously. We adopt a standard four-terminal electrical measurement and eliminate any contact contributions. We fabricated several tens of field-effect transistors (FETs) with MoS2 nanosheets exfoliated from the same MoS2 bulk. The MoS2 FETs can be grouped into either high- or low-mobility devices according to their temperature behaviors of mobilities. With an RT mobility higher than similar to 25 or similar to 30 cm(2)V(-1)s(-1), the MoS2 FETs exhibit an increasing mobility with decreasing temperature, implying phonon scattering in these high-mobility (HM) devices. The HM devices are accompanied with metallic states and their conductivities close to - 1 e2/h. A low specific contact resistivity of similar to 450 Omega.pm is observed in these HM devices. In contrast, the MoS2 FETs with an RT mobility lower than similar to 30 or similar to 35 cm(2)V(-1)s(-1), categorized as low-mobility (LM) devices, reveal a decreasing mobility with decreasing temperature. These LM devices show an insulating state, carriers suffering from impurity scattering, and a high contact resistance. Their temperature dependent resistances are highly concordant with the 2D Mott's variable range hopping. These observations corroborate a large variation of intrinsic disorders in MoS2 nanosheets.

Automated summary

The mobility of MoS2 nanosheets plays a significant role in nanoelectronics applications, with devices categorized into high-mobility and low-mobility based on their temperature-dependent behaviors. The high-mobility devices exhibit increasing mobility with decreasing temperature, showing phonon scattering, metallic states, and low contact resistivity; while the low-mobility devices display decreasing mobility, insulating states, impurity scattering, and high contact resistance, with temperature dependent resistances following Mott's variable range hopping. The observations suggest a wide range of intrinsic disorders in MoS2 nanosheets.