Enhancing thermoelectric performance in AgBiTe₂ alloys through band modification and localized lattice engineering

This study investigates the thermoelectric properties of oriented, non-stoichiometric AgBiTe₂ thin films, focusing on performance enhancement through band modification and localized lattice engineering. Band modification, primarily induced by the non-stoichiometric composition, leads to increased intrinsic defect concentrations and the formation of AgTe secondary phases, which enhance electrical conductivity with rising temperature. In parallel, localized lattice engineering, achieved via post-annealing, improves crystallinity, introduces energy filtering grain boundaries, and creates localized states, all of which contribute to a significant increase in the Seebeck coefficient, from 22.1 µV/K (as-deposited) to 42.35 µV/K (annealed at 673 K). These combined effects result in a thermoelectric power factor of 8.2 µW/cm K² at 450 K. Structural analyses (XRD and SEM) confirm the presence of AgTe phases and well-defined grain boundaries formed during annealing. Overall, the study highlights how the synergistic roles of band modification and localized lattice engineering can effectively enhance the thermoelectric performance of AgBiTe₂ thin films, positioning them as promising candidates for thermoelectric applications.