Plasmon-induced Ag decorated CeO₂ nanorod array for photodetector application

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Cerium oxide (CeO2) nanostructures are promising for optoelectronic devices.
• Silver nanoparticles (Ag NPs) can enhance optical properties through localized surface plasmon resonance (LSPR).

Purpose of the Study:

• To fabricate and characterize Ag decorated CeO2 nanorod (NR) arrays on silicon substrates.
• To investigate the LSPR effect of Ag NPs on the optoelectronic properties of CeO2 NRs.
• To evaluate the performance of the Ag/CeO2 heterojunction as a UV photodetector.

Main Methods:

• Glancing angle deposition (GLAD) was employed to grow CeO2 NRs decorated with Ag NPs.
• X-ray diffraction (XRD) and selected area electron diffraction (SAED) were used for structural analysis.
• Optical absorption, current-voltage measurements, and photoresponse tests were conducted.

Main Results:

• CeO2 NRs of ~235 nm length with Ag NPs (13-41 nm) were successfully synthesized.
• A distinct LSPR peak was observed around 413 nm, confirming the presence of Ag NPs.
• The Ag/CeO2 photodetector showed a reduced turn-on voltage under illumination and a significant increase in current.
• High responsivity (4.51 A W⁻¹ at 370 nm), detectivity (4.15 × 10¹² jones), and fast response times (74 ms rise, 42 ms fall) were achieved.

Conclusions:

• The LSPR effect of Ag NPs significantly enhances the photoresponse of CeO2 NRs.
• The fabricated Ag/CeO2 heterojunction demonstrates excellent performance as a UV photodetector.
• These findings highlight the potential of Ag/CeO2 nanostructures for advanced optoelectronic applications.