Surface Modification of ZnO Nanotubes by Ag and Au Coatings of Variable Thickness: Systematic Analysis of the Factors Leading to UV Light Emission Enhancement

Overview

Journal ACS Omega

Publisher American Chemical Society

Specialty Chemistry

Date 2024 Jan 15

PMID 38222608

Authors

Maksymilian Wlodarski

Michal P Nowak

Matti Putkonen

Piotr Nyga

Malgorzata Norek

Affiliations

Soon will be listed here.

Abstract

Surface modification by plasmonic metals is one of the most promising ways to increase the band-to-band excitonic recombination in zinc oxide (ZnO) nanostructures. However, the metal-induced modulation of the UV light emission depends strongly on the production method, making it difficult to recognize the mechanism responsible for charge/energy transfer between the semiconductor and a metal. Therefore, in this study, the ZnO/Ag and Au hybrids were produced by the same, fully controlled experimental approach. ZnO nanotubes (NTs), fabricated by a template-assisted ALD synthesis, were coated by metals of variable mass thickness (1-6.5 nm thick) using the electron beam PVD technique. The deposited Ag and Au metals grew in the form of island films made of metallic nanoparticles (NPs). The size of the NPs and their size distribution decreased, while the spacing between the NPs increased as the mass of the deposited Ag and Au metals decreased. Systematic optical analysis allowed us to unravel a specific role of surface defects in ZnO NTs in the processes occurring at the ZnO/metal interface. The enhancement of the UV emission was observed only in the ZnO/Ag system. The phenomena were tentatively ascribed to the coupling between the defect-related (DL) excitonic recombination in ZnO and the localized surface plasmon resonance (LSPR) at the Ag NPs. However, the enhancement of UV light was observed only for a narrow range of Ag NP dimensions, indicating the great importance of the size and internanoparticle spacing in the plasmonic coupling. Moreover, the enhancement factors were much stronger in ZnO NTs characterized by robust DL-related emission before metal deposition. In contrast to Ag, Au coatings caused quenching of the UV emission from ZnO NTs, which was attributed to the uncoupling between the DL and LSP energies in this system and a possible formation of the ohmic contact between the Au metal and the ZnO.

References

Zhou X, Jiang M, Wu Y, Ma K, Liu Y, Wan P . Hybrid quadrupole plasmon induced spectrally pure ultraviolet emission from a single AgNPs@ZnO:Ga microwire based heterojunction diode. Nanoscale Adv. 2022; 2(3):1340-1351. PMC: 9417069. DOI: 10.1039/c9na00777f. View

Huang T, Xu X . Synthesis and Characterization of Tunable Rainbow Colored Colloidal Silver Nanoparticles Using Single-Nanoparticle Plasmonic Microscopy and Spectroscopy. J Mater Chem. 2012; 20(44):9867-9876. PMC: 3375700. DOI: 10.1039/C0JM01990A. View

Qin F, Xu C, Zhu Q, Lu J, You D, Xu W . Extra green light induced ZnO ultraviolet lasing enhancement assisted by Au surface plasmons. Nanoscale. 2017; 10(2):623-627. DOI: 10.1039/c7nr07846c. View

Liszewska M, Budner B, Norek M, Jankiewicz B, Nyga P . Revisiting semicontinuous silver films as surface-enhanced Raman spectroscopy substrates. Beilstein J Nanotechnol. 2019; 10:1048-1055. PMC: 6541363. DOI: 10.3762/bjnano.10.105. View

Do T, Ho T, Bui T, Pham Q, Giang H, Do T . Surface-plasmon-enhanced ultraviolet emission of Au-decorated ZnO structures for gas sensing and photocatalytic devices. Beilstein J Nanotechnol. 2018; 9:771-779. PMC: 5852533. DOI: 10.3762/bjnano.9.70. View

Ruiz Peralta M, Pal U, Zeferino R . Photoluminescence (PL) quenching and enhanced photocatalytic activity of Au-decorated ZnO nanorods fabricated through microwave-assisted chemical synthesis. ACS Appl Mater Interfaces. 2012; 4(9):4807-16. DOI: 10.1021/am301155u. View

Djurisic A, Leung Y . Optical properties of ZnO nanostructures. Small. 2006; 2(8-9):944-61. DOI: 10.1002/smll.200600134. View

Zhang Y, Li X, Ren X . Effects of localized surface plasmons on the photoluminescence properties of Au-coated ZnO films. Opt Express. 2009; 17(11):8735-40. DOI: 10.1364/oe.17.008735. View

Zhao J, Cui S, Zhang X, Li W . Significantly enhanced UV luminescence by plasmonic metal on ZnO nanorods patterned by screen-printing. Nanotechnology. 2018; 29(35):355703. DOI: 10.1088/1361-6528/aacb52. View

10.

Sun K, Li Y, Saint John D, Jackson T . pH-controlled selective etching of Al2O3 over ZnO. ACS Appl Mater Interfaces. 2014; 6(10):7028-31. DOI: 10.1021/am501912q. View

11.

Shao D, Sun H, Yu M, Lian J, Sawyer S . Enhanced ultraviolet emission from poly(vinyl alcohol) ZnO nanoparticles using a SiO2-Au core/shell structure. Nano Lett. 2012; 12(11):5840-4. DOI: 10.1021/nl3031955. View

12.

Li G, Chen R, Guo D, Wong L, Wang S, Sun H . Nanoscale semiconductor-insulator-metal core/shell heterostructures: facile synthesis and light emission. Nanoscale. 2011; 3(8):3170-7. DOI: 10.1039/c1nr10352k. View

13.

Wang L, Wang X, Mao S, Wu H, Guo X, Ji Y . Strongly enhanced ultraviolet emission of an Au@SiO2/ZnO plasmonic hybrid nanostructure. Nanoscale. 2016; 8(7):4030-6. DOI: 10.1039/c5nr06153a. View

14.

Wang X, Ye Q, Bai L, Su X, Wang T, Peng T . Enhanced UV Emission from ZnO on Silver Nanoparticle Arrays by the Surface Plasmon Resonance Effect. Nanoscale Res Lett. 2021; 16(1):8. PMC: 7791003. DOI: 10.1186/s11671-020-03470-2. View

15.

Zhang Z, Yates Jr J . Band bending in semiconductors: chemical and physical consequences at surfaces and interfaces. Chem Rev. 2012; 112(10):5520-51. DOI: 10.1021/cr3000626. View

16.

Chen H, Kou X, Yang Z, Ni W, Wang J . Shape- and size-dependent refractive index sensitivity of gold nanoparticles. Langmuir. 2008; 24(10):5233-7. DOI: 10.1021/la800305j. View

17.

Prajapati K, Johns B, Bandopadhyay K, Silva S, Mitra J . Interaction of ZnO nanorods with plasmonic metal nanoparticles and semiconductor quantum dots. J Chem Phys. 2020; 152(6):064704. DOI: 10.1063/1.5138944. View