Designing 2D Metal–Semiconductor Junctions for Optoelectronics: A Comprehensive Consideration of Static Electronic Structures and Excited-State Carrier Dynamics

Two-dimensional metal-semiconductor junctions (MSJs) are crucial for nanoscale optoelectronics due to their atomically thin interfaces and tunable electronic properties. However, current theoretical studies primarily rely on ground-state properties, lacking comprehensive consideration of excited-state carrier extraction and recombination dynamics. Herein, taking 32 MSJs composed of transition-metal dichalcogenide lateral heterojunctions and MXene metals as examples, we investigate both ground-state electronic structures and interfacial carrier transport dynamics using density functional theory and non-adiabatic molecular dynamics. Four Type-II lateral heterojunctions enable efficient electron-hole separation, suppress wave function overlap, and prolong carrier lifetimes to the nanosecond scale. In metal-semiconductor contacts, Ohmic interfaces with low transport barriers are achieved through suitable work function alignment. Crucially, strong interlayer breathing vibrational modes enhance interfacial electron-phonon coupling, enabling picosecond-scale carrier extraction. This significant time-scale difference between extraction and recombination ensures efficient optoelectronic performance. Our integrated static-dynamic evaluation scheme paves the way for designing high-performance 2D optoelectronic devices.