Synthesis of PbO nanoparticles/porous Si/c-Si photodetector by one-step laser ablation in liquid
摘要
Nanostructured semiconductors play an important role in improving the performance of photodetectors due to their distinctive physical and chemical properties, which differ significantly from bulk materials. Their high surface-to-volume ratio, quantum confinement effects, and tunable bandgap enable improved light absorption, charge carrier separation, and transport. We present one- step synthesis of PbO nanoparticles via laser ablation in water, performed without any catalyst. X-ray diffraction (XRD) analysis confirms that the formation of α-PbO nanoparticles with tetragonal structure. Optical characterization indicates an energy bandgap of 3.02 eV for the PbO nanoparticles. Scanning electron microscopy (SEM) reveals that the nanoparticles are spherical, with an average size of approximately 64 nm. Additionally, a PbO nanoparticle-embedded porous silicon photodetector was successfully fabricated using electrochemical etching. The current-voltage characteristics of the PbO/PSi/c-Si photodetector exhibit a rectifying behavior, and its photosensitivity was 210 at – 8 V. The responsivity of the photodetector was 0.53 A/W at 410 nm, and the external quantum efficiency was 97% at 390 nm. The photodetector exhibited a detectivity (D*) of 1.864 × 10¹² cm Hz1/2 W-1 and a noise equivalent power (NEP) of 0.53 pW at a wavelength of 410 nm. An energy band diagram under illumination was constructed to clarify the charge carrier separation and transport mechanism in the PbO/PSi/c-Si heterojunction photodetector.