Effects of electric field and interlayer coupling on Schottky barrier of germanene/MoSSe vertical heterojunction

Among the many two-dimensional materials, germanene and Janus MoSSe have received considerable attention due to their novel electrical and optical properties. We anticipate that the heterojunction formed by germanene and MoSSe will exhibit exceptional properties and immense potential for applications in optoelectronic devices. Here, germanene/MoSSe vertical heterojunctions (VHJs) have been constructed by stacking the twisted bilayers, and their electronic properties, structural stability, and interface characteristics are calculated by applying the density functional theory. Meanwhile, the ab initio molecular dynamics simulation shows that the germanene/MoSSe VHJs are thermodynamically stable, and the germanene/SeMoS (Ge/SeMoS) VHJ is more energetically stable than germanene/SMoSe (Ge/SMoSe) VHJ. The Schottky contact is formed in the germanene/MoSSe heterojunctions. In particular, the Schottky barrier of Ge/SeMoS VHJ can be modulated by the electric field, resulting in the change of Schottky contact from p-type to n-type, even to Ohmic contact. However, the change in interlayer distance also can lead to variation of the Schottky barrier, but the contact type is unchanged. In addition, the Ge/SeMoS VHJ exhibits an excellent light absorption performance. Therefore, the Ge/SeMoS VHJ is a potential material for the design and fabrication of optoelectronic devices.