Tunable temperature coefficient of resistance in PdSe2 films enabled by strain engineering

Abstract

Abstract Two-dimensional (2D) semiconductors, owing to their exceptional physical properties, show tremendous promise for developing high-performance bolometers and temperature sensors. Yet the temperature coefficient of resistance (TCR), the figure of merit that dictates the sensitivity of such thermosensitive devices, is typically fixed once the material is synthesized, precluding post-fabrication optimization for specific applications. Herein, we demonstrate that the TCR of PdSe 2 can be continuously and reversibly tuned in both directions through strain engineering. Under compressive strain the bandgap widens, whereas it narrows under tensile strain. This band structure reconfiguration translates directly into a controllable shift in TCR. Flexible PdSe 2 sensors fabricated on plastic substrates exhibit exceptionally wide TCR tunability: a modest − 0.63% compressive strain boosts the TCR value by 24.3% (from − 3.7% to − 4.6% °C − 1 ), while 0.56% tensile strain suppresses it by 18.9% (from − 3.7% down to − 3.0% °C − 1 ). Such excellent TCR tunability, together with the advantages of low-temperature and large-area fabrication, makes the PdSe 2 films highly promising for developing reconfigurable electronic skins, adaptive temperature sensors, and next-generation smart wearable sensing devices.