Interfacial Band Engineering for Enhanced Thermoelectric Performance in GaN/WSeTe van der Waals Heterostructures: A DFT-NEGF Study

Low-dimensional thermoelectric materials have gained substantial attention due to their ability to generate higher energy conversion efficiency through interlayer coupling. In the present work, we examine the transport characteristics of GaN/WSeTe vdWHs using density functional theory. Initially, the geometric structure was fully relaxed, and the electronic characteristics were subsequently analyzed. The dispersive energy curve and PDOS reveal the staggered alignment at the interlayer, facilitating carrier transport. The non-equilibrium Green’s function (NEGF) formalism is utilized to analyze the critical factor influencing the thermoelectric characteristics. The conductance of GaN/WSeTe vdWHs significantly enhances the interlayer coupling, which facilitates the electron transport and suppresses the interface scattering. Meanwhile, the Seebeck coefficient is decreased monotonically with the thermal broadening, which weakens the energy filtering effect. Furthermore, the thermoelectric figure of merit has achieved 1.00 ≤ ZT ≤ 3.63 at μ = 0.58 eV and 0.89 ≤ ZT ≤ 2.36 at μ = –0.29 eV for Se-4 and Te-3 GaN/WSeTe vdWHs at elevated temperatures (300–900 K). These results demonstrate that the hybrid is a promising next-generation thermoelectric material, with potential applications in renewable energy technologies.