Plasmon-induced Ag decorated CeO <sub>2</sub> nanorod array for photodetector application
Ngasepam Monica Devi, Naorem Khelchand Singh
Abstract
Abstract In this work, glancing angle deposition (GLAD) has been used to grow Ag decorated CeO 2 nanorod (NR) array on n-type Si substrate. The length of the NRs obtained was ∼235 nm and the size of the Ag NPs varied from 13 to 41 nm. The polycrystalline and crystalline nature of CeO 2 and Ag respectively was revealed via selected area electron diffraction (SAED) analysis as well as x-ray diffraction (XRD) pattern. Optical absorption measurement depicts a distinct broad peak around 413 nm that is ascribed to the localized surface plasmon resonance (LSPR) effect of Ag NPs. The Ag decorated CeO 2 NR device exhibited a turn on voltage at ∼3.2 V under dark, which then reduced to ∼1.3 V under 35 min illumination along with the increase in device current from 2.8 to 24.5 μ A cm −2 (4 V) on continuous exposure to light. Under white light illumination, a responsivity of 4.51 A W −1 was obtained at 370 nm along with the detectivity and noise equivalent power (NEP) values of 4.15 × 10 12 jones and 0.01 pW respectively. Additionally, a fast response characteristic with rise and fall times of 74 ms and 42 ms respectively was demonstrated. Thus, these findings manifest the underlying LSPR mechanism at work in Ag/CeO 2 heterojunction and reveal its high potential in UV photodetector application.