Review of Ultrafast Spectroscopy Studies of Valley Carrier Dynamics in Two Dimensional Semiconducting Transition Metal Dichalcogenides

TL;DR

This paper reviews ultrafast spectroscopy techniques used to study the dynamics of valley-related electronic states, especially excitons, in two-dimensional transition metal dichalcogenides, highlighting recent experimental advances.

Contribution

It provides a comprehensive overview of experimental ultrafast spectroscopy studies on valley carrier dynamics in monolayer TMDs, emphasizing helicity resolved pump-probe methods.

Findings

Ultrafast spectroscopy reveals exciton dynamics in TMDs.

Helicity resolved techniques distinguish valley-specific electronic processes.

Recent experiments advance understanding of valley polarization and relaxation.

Abstract

The two dimensional layered transition metal dichalcogenides provide new opportunities in future valley based information processing and also provide ideal platform to study excitonic effects. At the center of various device physics toward their possible electronic and optoelectronic applications is understanding the dynamical evolution of various many particle electronic states, especially exciton which dominates the optoelectronic response of TMDs, under the novel context of valley degree of freedom. Here, we provide a brief review of experimental advances in using helicity resolved ultrafast spectroscopy, especially ultrafast pump-probe spectroscopy, to study the dynamical evolution of valley related many particle electronic states in semiconducting monolayer transitional metal dichalcogenides.