Janus MoSH/WSi2N4 van der Waals Heterostructure: Two-Dimensional Metal/Semiconductor Contact.

Constructing heterostructures from already synthesized two-dimensional materials is of significant importance. We performed a first-principles study to investigate the electronic properties and interfacial characteristics of Janus MoSH/WSi2N4 van der Waals heterostructure (vdWH) contacts. We demonstrate that the p-type Schottky formed by MoSH/WSi2N4 and MoHS/WSi2N4 has extremely low Schottky barrier heights (SBHs). Due to its excellent charge injection efficiency, Janus MoSH may be regarded as an effective metal contact for WSi2N4 semiconductors. Furthermore, the interfacial characteristics and electronic structure of Janus MoSH/WSi2N4 vdWHs can not only reduce/eliminate SBH, but also forms the transition from p-ShC to n-ShC type and from Schottky contact (ShC) to Ohmic contact (OhC) through the layer spacing and electric field. Our results can offer a fresh method for optoelectronic applications based on metal/semiconductor Janus MoSH/WSi2N4 vdW heterostructures, which have strong potential in optoelectronic applications.

Tunable electrical contact properties in two-dimensional van der Waals V2C/MoSi2N4heterostructures.

Two-dimensional MoSi2N4is a member of the emerging 2D MA2N4family, which has been synthesized in experiments, recently. Herein, we conduct a first-principles investigation to study more about the atomic and electronic structures of V2C/MoSi2N4(1T-phase) van der Waals heterostructures (vdWHs) and interlayer distance and an external perpendicular electric field change their tunable electronic structures. We demonstrate that the V2C/MoSi2N4vdWHs contact forms n-type Schottky contact with an ultralow Schottky barrier height of 0.17 eV, which is beneficial to enhance the charge injection efficiency. In addition, the electronic structure and interfacial properties of V2C/MoSi2N4vdWHs can be transformed from n-type to p-type ShC through the effect of layer spacing and electric field. At the same time, the transition from ShC to OhC can also occur by relying on the electric field and different interlayer spacing. Our findings could give a novel approach for developing optoelectronic applications based on V2C/MoSi2N4vdW heterostructures.

Tunable Contact Types and Interfacial Electronic Properties in TaS2/MoS2 and TaS2/WSe2 Heterostructures.

Following the successful experimental synthesis of single-layer metallic 1T-TaS2 and semiconducting 2H-MoS2, 2H-WSe2, we perform a first-principles study to investigate the electronic and interfacial features of metal/semiconductor 1T-TaS2/2H-MoS2 and 1T-TaS2/2H-WSe2 van der Waals heterostructures (vdWHs) contact. We show that 1T-TaS2/2H-MoS2 and 1T-TaS2/2H-WSe2 form n-type Schottky contact (n-ShC type) and p-type Schottky contact (p-ShC type) with ultralow Schottky barrier height (SBH), respectively. This indicates that 1T-TaS2 can be considered as an effective metal contact with high charge injection efficiency for 2H-MoS2, 2H-WSe2 semiconductors. In addition, the electronic structure and interfacial properties of 1T-TaS2/2H-MoS2 and 1T-TaS2/2H-WSe2 van der Waals heterostructures can be transformed from n-type to p-type Schottky contact through the effect of layer spacing and the electric field. At the same time, the transition from Schottky contact to Ohmic contact can also occur by relying on the electric field and different interlayer spacing. Our results may provide a new approach for photoelectric application design based on metal/semiconductor 1T-TaS2/2H-MoS2 and 1T-TaS2/2H-WSe2 van der Waals heterostructures.