  Disorder derived from defects or strain in monolayer TMDs can lead to a
dramatic change in the physical behavior of the interband excitations,
producing inhomogeneous spectral broadening and localization; leading to
radiative lifetime increase. In this study, we have modeled the disorder in the
surface of the sample through a randomized potential in monolayer WSe2. We show
that this model allows us to simulate the spectra of localized exciton states
as well as their radiative lifetime. In this context, we give an in depth study
of the influence of the disorder potential parameters on the optical properties
of these defects through energies, density of states, oscillator strengths,
photoluminescence (PL) spectroscopy and radiative lifetime at low temperature
(4K). We demonstrate that localized excitons have a longer emission time than
free excitons, in the range of tens of picoseconds or more, and we show that it
depends strongly on the disorder parameter and dielectric environment. Finally,
in order to prove the validity of our model we compare it to available
experimental results of the literature.
