Temperature dependence of photoluminescence lifetime of atomically thin WSe2 layer

TL;DR

This study investigates how the photoluminescence lifetime of monolayer WSe2 decreases with temperature, revealing that nonradiative relaxation channels become dominant at higher temperatures, affecting localized exciton emission.

Contribution

It provides the first time-resolved measurement linking temperature-dependent PL intensity decrease to nonradiative relaxation in monolayer WSe2.

Findings

PL decay time decreases with temperature

Nonradiative channels dominate at higher temperatures

Localized exciton emission is quenched by thermal effects

Abstract

At cryogenic temperatures, the photoluminescence spectrum of monolayer WSe2features a num-ber of lines related to the recombination of so-called localized excitons. The intensity of these lines strongly decreases with increasing temperature. In order to understand the mechanism behind this phenomenon, we carried out a time-resolved experiment, which revealed a similar trend in the photoluminescence decay time. Our results identify the opening of additional nonradiative relaxation channels as a primary cause of the observed temperature quenching of the localized excitons' photoluminescence.