Regulation Mechanism of Functional Group Type and Concentration Gradient Doping on Interfacial Electronic Properties and Charge Transfer in Zr ₂ CT _<i>x</i> –MoS ₂ Heterojunctions

This study constructed the Zr₂CT_<i>x</i>-MoS₂ vdW-HS and focused on discussing the modulation mechanisms and trends of the SBH in this system under the influence of different functional group types (-F/-O/-OH) and concentration gradients (0%, 25%, 50%, 75%, 100%). Phonon spectrum and interfacial binding energy calculations revealed that all structures possess stability. Systems with >50% -O concentration exhibited bandgaps, enabling heterojunction bandgap modulation between 0.02 and 1.35 eV. Opposite trends emerged between n-type (Φ_e) and p-type (Φ_h) SBH: in -O systems, increasing -O concentration progressively decreased Φ_h while increasing Φ_e, yielding maximum/minimum Φ_e values of 0.668/-0.362 eV and Φ_h values of 1.366/0.418 eV. Systems with -OH doped into -F configurations exhibited stable SBH variations, with n-type Ohmic contacts emerging repeatedly during functional group doping and tuning processes. These phenomena originate from doping-induced work function changes (2.0-4.3 eV range), where altered work function differences drive interfacial charge redistribution. This subsequently modulates the direction and magnitude of MoS₂ band bending, ultimately shifting its CBM and VBM to achieve SBH control. These findings provide a theoretical basis for designing and optimizing high-performance two-dimensional semiconductor devices that are more miniaturized and have lower contact resistance.