Zirconium Dichalcogenide-Based van der Waals Heterostructures for Efficient Schottky Barrier Solar Cells

We present our study of bilayered heterostructures consisting of a metallic ZrTe2(1T) monolayer and a semiconducting ZrSe2(1T) monolayer leading to a bilayered Schottky contact. We have confirmed the dynamic stability of this bilayered heterostructure using phonon dispersion spectra and the structural stability from the binding energy value. We have performed ladder calculations, namely, density functional theory for structural relaxation and electronic self-consistency; final electronic structure for better estimation of the band gap with single-shot GW calculation; and solution of the Bethe-Salpeter equation to calculate the optical absorption spectrum for the system. Using this absorption spectrum, we have estimated the power conversion efficiency (PCE). Our estimated PCE for this (approximate to 1 nm thick) device is approximate to 1%, leading to a considerably high power density value. This bilayered heterostructure has not been studied to date in the literature theoretically or experimentally and we have demonstrated its potential application as a Schottky barrier solar cell. Our study predicts that the ZrSe2(1T)@ZrTe2(1T) bilayered heterostructure is a suitable material for an ultrathin Schottky barrier solar cell.