Hydrothermally synthesized Sm ₂ O ₃ nanoparticles for high-performance self-powered photodetectors

Abstract This study reports the successful synthesis and characterization of samarium oxide nanoparticles (Sm 2 O 3 NPs) and their integration into a high-performance Au/Sm 2 O 3 /n-Si heterojunction photodetector. Scanning electron microscope /x-ray spectroscopy analyses revealed that the synthesized Sm 2 O 3 NPs form a porous film composed of mixed-shaped particles, confirming the deposition of high-purity Sm 2 O 3 on n-Si substrate. Ultraviolet–visible spectroscopy indicated strong ultraviolet (UV) absorption in the 345–430 nm range and a direct band gap of 3.4 eV, consistent with previously reported values for Sm 2 O 3 nanostructures. X-ray photoelectron spectroscopy analysis further confirmed the chemical composition and surface chemistry of the NPs. To evaluate their device potential, Sm 2 O 3 NPs films were deposited on n-type silicon substrates to fabricate Au/Sm 2 O 3 /n-Si heterojunction photodetectors. The devices exhibited excellent rectifying behavior and a notable self-powered photoresponse. Under 395 nm UV illumination at zero bias, the device demonstrated a photoresponsivity of 0.1 A W −1 , a specific detectivity of 1.04 × 10 12 Jones, a noise-equivalent power (NEP) of 8.5 × 10 −14 WHz −0.5 , and a normalized photo-to-dark current ratio (NPDR) of 4.48 × 10 8 W −1 . Stability tests, assessed through initial and 90 d I–V measurements, showed a minor decline in performance while maintaining functional operation. These results highlight the promise of Sm 2 O 3- based heterostructures for, wavelength-selective, and self-powered UV photodetectors.