Trion induced negative photoconductivity in monolayer MoS2

Abstract

Optical excitation typically enhances electrical conduction and low-frequency radiation absorption in semiconductors. We have, however, observed a pronounced transient decrease of conductivity in doped monolayer molybdenum disulfide (MoS2), a two-dimensional (2D) semiconductor, under femtosecond laser excitation. In particular, the conductivity is reduced dramatically down to only 30% of its equilibrium value with high pump fluence. This anomalous phenomenon arises from the strong many-body interactions in the system, where photoexcited electron-hole pairs join the doping-induced charges to form trions, bound states of two electrons and one hole. The resultant increase of the carrier effective mass substantially diminishes the carrier conductivity.

References in corpus (9)

• Valley polarization in MoS2 monolayers by optical pumping
• Synthesis of Large-Area MoS2 Atomic Layers with Chemical Vapor Deposition
• Observation of giant bandgap renormalization and excitonic effects in a monolayer transition metal dichalcogenide semiconductor
• Tightly bound excitons in monolayer WSe2
• Probing Excitonic Dark States in Single-layer Tungsten Disulfide
• Non-linear Optical Spectroscopy of Excited Exciton States for Efficient Valley Coherence Generation in WSe2 Monolayers
• Ultrafast and spatially resolved studies of charge carriers in atomically-thin molybdenum disulfide
• Semiconducting-to-metallic photoconductivity crossover and temperature-dependent Drude weight in graphene
• Observation of suppressed terahertz absorption in photoexcited graphene

Cited by in corpus (4)

• Diffusion quantum Monte Carlo study of excitonic complexes in two-dimensional transition-metal dichalcogenides
• Optically discriminating carrier-induced quasiparticle band gap and exciton energy renormalization in monolayer MoS2
• Excitons and trions in monolayer transition metal dichalcogenides: A comparative study between the multiband model and the quadratic single-band model
• Ultrafast Terahertz Probe of Transient Evolution of Charged and Neutral Phase of Photoexcited Electron-hole Gas in Monolayer Semiconductor