Two-dimensional ZrSe2/ZrS2 heterobilayer tuned by electric field for optoelectronic devices

Constructing two-dimensional heterostructures can obtain more desirable device performance. In this work, we discuss the electronic properties and optical absorption of ZrSe2/ZrS2 van der Waals (vdW) heterobilayer by density function theory. ZrSe2/ZrS2 heterobilayer presents an intrinsic type-II band alignment, and the electrons and holes can be separated in different layers of ZrSe2/ZrS2 heterobilayer, which can improves its carrier lifetime in photovoltaic devices. The electric field can effectively adjust the electronic properties of heterostructures. By applying a certain electric field, the band alignment can realize the transition from type-II to type-I, which is very beneficial to optical emission devices. To understand the inherent physical mechanism of electric field modulation, we analyze the variation trends of the band gap and band offset with external field in detail. In addition, ZrSe2/ZrS2 heterostructure presents much stronger light absorption than isolated monolayers. Our results suggest that ZrSe2/ZrS2 heterostructure can provide more potential application in optoelectronic devices.