Long Non-Exponential PL Decay from Localized Defect States in Monolayer WSe$_2$ at Low Temperature

Immanuel Thekkooden; Susmitha Jana; Mrinal Deka; B. R. K. Nanda; V Praveen Bhallamudi

Long Non-Exponential PL Decay from Localized Defect States in Monolayer WSe$_2$ at Low Temperature

Materials Science 2026-07-20 v1

Authors: Immanuel Thekkooden , Susmitha Jana , Mrinal Deka , B. R. K. Nanda , V Praveen Bhallamudi

Abstract

We investigate the recombination dynamics of localized defect emission in monolayer WSe $_2$ using time-resolved photoluminescence over the temperature range from 4 to 120 K. The defect emission comprises a dominant sub-nanosecond exponential component and two weak, long-lived power-law channels extending from a few nanoseconds to several hundred nanoseconds. The power-law relaxation admits an interpretation in terms of continuous distributions of recombination lifetimes associated with an inhomogeneous ensemble of localized states. Temperature-dependent measurements were performed to examine the thermal detrapping mechanisms governing these long-lived channels. Spin-resolved electronic-structure and optical-transition calculations provide microscopic insight into the localized states and the available recombination pathways. These results provide a framework for understanding long-lived, non-exponential defect recombination in two-dimensional semiconductors.

Keywords

WSe2 defect emission photoluminescence time-resolved power-law decay localized states two-dimensional semiconductors

Cite

@article{arxiv.2607.18423,
  title  = {Long Non-Exponential PL Decay from Localized Defect States in Monolayer WSe$_2$ at Low Temperature},
  author = {Immanuel Thekkooden and Susmitha Jana and Mrinal Deka and B. R. K. Nanda and V Praveen Bhallamudi},
  journal= {arXiv preprint arXiv:2607.18423},
  year   = {2026}
}