Twist-Dependent Tuning of Excitonic Emissions in Bilayer WSe<sub>2</sub>
Prahalad Kanti Barman, Pranshoo Upadhyay, Ramesh Rajarapu, Sharad Kumar Yadav, K. V. P. Latha, N. Meenakshisundaram, Pramoda K. Nayak
Abstract
, grown using chemical vapor deposition (CVD), with t-angle in the range of 0 ≤ θ ≤ 60°. Systematic analyses based on Raman and photoluminescence (PL) spectroscopies suggest intriguing deviations in the interlayer interactions, higher-energy exciton transitions (in the range of ∼1.6-1.7 eV), and stacking. In contrast to previous observations, we demonstrate a red shift in the PL spectra with t-angle. Density functional theory (DFT) is employed to understand the band-gap variations with t-angle. Exciton radiative lifetime has been estimated theoretically using temperature-dependent PL measurements, which shows an increase with t-angle that agrees with our experimental observations. This study presents the groundwork for further investigation of the evolution of various interlayer excitons and their dynamics with t-angle in homobilayer systems, critical for optoelectronic applications.