The Contacts of the Monolayer Semiconductor C 2 N with 2D Metal Electrodes

For its easy synthesis, suitable band gap, and fine optoelectronic properties, the carbon nitride sheet C 2 N acts as a promising candidate material for nanoelectronics. To achieve a high‐performance C 2 N device, ohmic contact with metal electrodes is urgently needed. Here, based on first principles calculations, the monolayer (ML) C 2 N contacts with a series of 2D metal electrodes—surface‐engineered MXenes (Hf 2 C(OH) 2 , Nb 2 CF 2 , Mo 2 NO 2 ) and metallic transition metal dichalcogenides ( T ‐VSe 2 , T ‐VS 2 , H ‐TaS 2 )—are systematically studied. With clean and saturated surfaces, these 2D metals form van der Waals (vdW) contacts with C 2 N, which exhibit a weak Fermi level pinning and tunable Schottky barriers. While n‐type Schottky barriers are observed for Nb 2 CF 2 / T ‐VSe 2 electrodes and p‐type for T ‐VS 2 /Mo 2 NO 2 / H ‐TaS 2 electrodes due to their different sizes of work functions, ohmic contact is found for Hf 2 C(OH) 2 electrode with its work function significantly smaller than electron affinity of ML C 2 N. Device simulations of field effect transistors based on C 2 N further confirmed the finding. This paper presents a fundamental understanding of 2D metal–C 2 N contacts and will help the future design of well‐performing C 2 N devices.