Ultrafast and spatially resolved studies of charge carriers in atomically-thin molybdenum disulfide

TL;DR

This study uses ultrafast pump-probe techniques to spatially and temporally analyze charge carrier dynamics in atomically-thin molybdenum disulfide, revealing key properties like lifetime, diffusion, and mobility.

Contribution

It provides the first spatially and temporally resolved measurements of charge carriers in atomically-thin molybdenum disulfide using pump-probe spectroscopy.

Findings

Measured carrier lifetime and diffusion length.

Determined carrier mobility in monolayer MoS2.

Mapped spatial distribution of charge carriers.

Abstract

Atomically-thin molybdenum disulfide is emerging as a new nanomaterial with potential applications in the fields of electronic and photonics. Charge carrier dynamics plays an essential role in determining its electronic and optical properties. We report spatially and temporally resolved pump-probe studies of charge carriers in atomically-thin molybdenum disulfide samples fabricated by mechanical exfoliation. Carriers are injected by interband absorption of a 390-nm pump pulse and detected by measuring differential reflection of a time-delayed and spatially-scanned probe pulse that is tuned to an exciton transition. Several parameters on charge carrier dynamics are deduced, including carrier lifetime, diffusion coefficient, diffusion length, and mobility.