Simulation Studies on Robust Contacts in V₂CT₂/MoSi₂N₄ (T═O, F, OH) van der Waals Heterojunction Nanostructures: Implications for Optoelectronic Devices

Research on metal electrode–semiconductor contacts has primarily focused on adjusting the Schottky barrier height (SBH), with little attention paid to the stability of electronic properties upon contact. Herein, we comprehensively investigate the sensitivity of contact properties to the external electric field (Δ E ), out-plane strain (Δ d ), and in-plane biaxial strain (Δδ) taking the V 2 C(T 2 )/MoSi 2 N 4 (T═O, OH, F) van der Waals heterojunction (vdWH) as an example. Our findings suggest that surface functionalization (-T termination) is a powerful tool for controlling contact characteristics. Importantly, when Δ E ═0.3 V/nm, Δ d = −0.1 Å, and Δδ < 0%, the intrinsic contact properties of V 2 C/MoSi 2 N 4 may be changed. However, V 2 CT 2 /MoSi 2 N 4 can maintain the intrinsic contact properties over a wider range of Δ E, Δ d, and Δδ. Furthermore, we design a p–i–n optoelectronic transistor (V 2 CO 2 /MoSi 2 N 4 /V 2 CO 2 H 2 ), which has excellent tunneling probability (100%), photocurrent density (11.336 A/m 2 ), responsivity (0.322 AW –1 ), and external quantum efficiency (71.061%). Our work not only serves as a reference for eliminating the error of information transmission and the degradation of device performance caused by contact property sensitivity to electric field and strain but also provides theoretical guidance for the experimental design of high-performance MoSi 2 N 4 -based optoelectronic devices.