MXenes for n- and p-type Ohmic contacts with Monolayer MoS2 and WS2: A first-principles study

Abstract

In the field of semiconductor devices, the contact characteristics between metal and semiconductor play a crucial role in determining device performance. Though first-principles calculations, systematic investigations on two prominent monolayer (ML) transition metal dichalcogenide (TMD) semiconductors, namely MoS₂ and WS₂, coupled with four ML MXene metals, are conducted. The TMD/MXene vertical heterojunctions exhibit van der Waals (vdW) type interactions, ensuring that the band structures of each component are well preserved. The formation of heterojunctions induces charge redistribution, which shifts the Fermi level. In the studied TMD/MXene vertical heterojunctions, the Fermi level shifts to the conduction or valence band edges of the ML semiconductor. Consequently, ML Zr₂NF₂ and Zr₂N(OH)₂ are identified as suitable n-type Ohmic contact electrodes for ML MoS₂ and WS₂, while ML Mo₂CO₂ serves as an effective p-type Ohmic contact electrode.