Boosting TTE performance in inclined PbSe thin films via Pb self-doping for high-sensitivity photodetection

Inclined PbSe thin films exhibit promising transverse thermoelectric (TTE) effect for self-powered ultraviolet pulsed and ultra-broadband continuous-wave (CW) photodetection, yet their performance requires further optimization for practical applications. We implemented a Pb self-doping strategy to enhance TTE performance of inclined PbSe thin films. Through precise modulation of the Pb/Se ratio (x), inclined PbSe thin films embedded with Pb nanoparticles were fabricated via pulsed laser deposition. Voltage sensitivity increased from 7.66 V/mJ to 11.36 V/mJ (48 % improvement) under 308 nm pulsed laser irradiation as x increased, with a 150 % enhancement achieved at x = 1.20 under 10,600 nm CW laser irradiation. Self-doping optimizes carrier concentration, simultaneously increasing electrical conductivity, reducing lattice thermal conductivity, and thereby achieving superior TTE performance. This work advances the understanding of self-doping in chalcogenides and provides a strategy for optimizing TTE detection performance. • A Pb self-doping strategy achieves substantial enhancements in the TTE performance of inclined PbSe thin films. • The precise modulation of Pb/Se ratio enables a significant improvement of photodetection sensitivity under both pulsed and broadband continuous-wave laser illumination in inclined Pb self-doped PbSe thin films. • Self-doping optimizes carrier concentration, simultaneously increasing electrical conductivity, reducing lattice thermal conductivity, and thereby achieving superior TTE performance.