Erbium Oxide Nanoparticles As Interfacial Layer For Self-Driven Uv-Vis Sensitive Silicon Photodetectors

This study investigates hydrothermally synthesized erbium oxide (Er2O3) nanoparticles (NPs) as an interfacial layer in an Au/Er2O3/n-Si/Al heterostructure and evaluates their influence on the electrical and photoelectrical properties of silicon photodetectors. The structural, optical, and chemical properties of the synthesized Er2O3 NPs were characterized using SEM, UV–Vis spectroscopy, XRD, and XPS techniques. UV–Vis analysis revealed an optical bandgap of 3.427 eV, indicating strong suitability for UV-related optoelectronic applications. Electrical characteristics were analyzed using I–V measurements under dark and illuminated conditions. Under dark conditions, the device with the Er2O3 interlayer exhibited improved junction characteristics with an ideality factor (n) of 1.79, a barrier height (Φb) of 0.78 eV, and a series resistance (Rs) of 150 kΩ, determined using thermionic emission (TE) and Norde methods. Under illumination, the Er2O3/n-Si photodetector showed strong photoresponse and clear self-powered operation with measurable photocurrent at 0V due to the built-in electric field at the heterojunction. The responsivity (R) and detectivity (D*) reached 0.033 A/W and 2.32×1010 Jones under 1 sun illumination at −0.5 V, and 0.064 A/W and 4.52×1010 Jones under UV (395 nm) illumination, respectively. Furthermore, the device achieved an external quantum efficiency (EQE) of 21.75%, a noise equivalent power (NEP) of 2.44×10-12 W Hz-0.5, and a normalized photo-to-dark current ratio (NPDR) of 7.79×105 W-1 under UV illumination at −2 V. These results demonstrate that hydrothermally synthesized Er2O3 NPs are an effective interfacial material and show strong potential for high-performance, low-power, and UV-sensitive silicon-based optoelectronic devices.