Surface Plasmon-Enhanced Light-Emission Mechanism of Ag-Coated ZnO/Al₂O₃ Core/Shell Nanorod Structures

Abstract

Surface plasmon (SP)-enhanced light emission mechanism has been investigated for the Ag-coated ZnO/Al2O3 core/shell nanorods (NRs). Structural characterizations showed that the ZnO NRs were covered by conformal Al2O3 layer and coated by Ag nanoparticles (NPs). The optical studies by photoluminescence (PL) showed abnormal variation of PL intensity with increasing the thickness of Al2O3. For the Ag NPs-coated ZnO NRs without Al2O3 shell layer, the PL emission quenched due to direct transfer of the photo-excited electrical carriers from ZnO NRs to Ag NPs. With thin Al2O3 layers less than 15 nm, the PL intensity increased with increasing the thickness of Al2O3 layers due to weakening of the Förster-type energy transfer while strong SP-mediated PL emission enhancement. For thicker Al2O3 layers than 15 nm, however, the PL intensity decreased with increasing the thickness of Al2O3 layers due to weakening of SP-mediated PL emission enhancement.

Surface-plasmon mediated photoluminescence enhancement of Pt-coated ZnO nanowires by inserting an atomic-layer-deposited Al2O3spacer layer

“…This is attributed to the exited electrons transferring from the conduction band of ZnO to the energy band of Pt NPs. This phenomenon is in good agreement with other works on the UV emission quenching of ZnO decorated with different metal NPs [26,27,[37][38][39][40]. It is interesting to find that a remarkable enhancement of ∼9.2 times the UVvisible emission ratio can be obtained in the ZnO NW/Pt sample compared to that of the bare ZnO NWs.…”

Plasmonic silver nanosphere enhanced ZnSe nanoribbon/Si heterojunction optoelectronic devices

“…The oscillating electrons (hot electrons) in the Ag NPs can be photo-excited to a high energy level, and can be transferred from the Ag NPs to the surface of the ZnSe NRs. This phenomenon has been reported in previous work, according to which the oscillating electrons in the Ag NPs can be readily transferred to the nearby II-VI nanostructures [40][41][42]. In this case, in addition to the general contribution of ZnSe: Sb NR/Si under light illumination, the photocurrent of the plasmonic optoelectronic device also enjoys the extra contribution from the plasmonic Ag NPs induced hot electron injection.…”

Hierarchical ZnO Nanorods on Si Micropillar Arrays for Performance Enhancement of Piezoelectric Nanogenerators

“…The ALD method provides a conformal coating of ZnO deposits, even on complicated structures, because of a long mean free path, and fewer gas-phase reactions of the sources in the deposition system. 22 Under our optimal deposition conditions, the growth rate of the ZnO films was 1.5 to 1.6 angstroms/cycle at a substrate temperature of 200 °C. ZnO NRs were grown on the ZnO seed layer-grown SiMP arrays using the low-temperature hydrothermal method.…”

“…A 5 nm thick ZnO thin film was deposited on the SiMP arrays as a seed layer using the atomic layer deposition (ALD) technique. The ALD method provides a conformal coating of ZnO deposits, even on complicated structures, because of a long mean free path, and fewer gas-phase reactions of the sources in the deposition system . Under our optimal deposition conditions, the growth rate of the ZnO films was 1.5 to 1.6 angstroms/cycle at a substrate temperature of 200 °C.…”