Interfacial Configuration Impact on Rashba Spin Splitting, Excitonic Radiative Lifetime and Band Edge Alignment in Janus Monolayers based Heterostructures

Abstract

In this work, we have explored two emerging Janus monolayers BiTeBr and SbTeBr, while constructing their corresponding heterostructures by varying the interfacial terminations. We have determined band edge alignment and excitonic radiative lifetime for four different heterostructures, which are turned out to be governed by the stacking pattern and different terminations at the interfaces. We have considered many body perturbation theory (MBPT) in addition to the ground state electronic structure calculations based on density functional theory (DFT) formalism. We have also determined the charge carrier mobility and photo-conversion efficiency(PCE) of the four possible heterostructure configurations, which are found to be sensitive depending upon the termination at the interface, as also being reflected in the Rashba spin splitting, excitonic radiative lifetime and band edge alignment. The constructed heterostructures are found to be thermodynamically and dynamically stable, while all of them show type-II band edge alignment. The photo-conversion efficiency varies significantly, ranging from 2.39% to 17.27% due to the enhancement of effective charge carrier separation originating from interlayer bright excitons with extended lifetimes reducing radiative decay