High-Efficiency Thermoelectric Energy Conversion in Gate-Tunable WSe ₂ Superlattice Nanojunctions

High Resolution Image Download MS PowerPoint Slide Two-dimensional transition-metal dichalcogenide (TMD) nanojunctions are promising candidates for nanoscale thermoelectric energy conversion. In this work, we investigate the thermoelectric properties of gate-tunable Pt–WSe 2 –Pt nanojunctions in the ballistic transport regime based on periodically nitrogen-doped monolayer WSe 2 superlattices. Electronic transport properties were calculated using density functional theory combined with the nonequilibrium Green’s function formalism (DFT-NEGF), while phonon thermal conductivities were obtained from nonequilibrium molecular dynamics (NEMD) simulations. Periodically nitrogen-doped WSe 2 superlattices with 4-, 6-, and 8-Row doping periodicities were systematically investigated and compared with pristine WSe 2 . The results show that periodic nitrogen doping reduces the band gap, sharpens transmission band edges, and suppresses phonon thermal conductivity. These effects lead to substantial enhancements in thermoelectric performance. Furthermore, the 4-Row superlattice achieves the highest thermoelectric figure of merit, reaching ZT = 2.587 at 500 K, compared with ZT = 0.422 for pristine WSe 2 . The enhanced performance originates from the combined effects of improved electronic transport engineered by band gap and reduced thermal conductivity by more scattering due to superlattice. These findings demonstrate that periodically nitrogen-doped WSe 2 superlattices provide an effective route for band-structure and phonon engineering, offering a promising strategy for high-efficiency thermoelectric energy conversion in two-dimensional nanoscale devices.