Enhanced Ultraviolet Photodetector Performance via Integration of Gold Nanoparticles on a 3M ZNO Thin Film

This paper presents a comprehensive investigation into the enhancement of ultraviolet (UV) photodetector (PD) performance achieved by integrating gold nanoparticles (Au NPs) onto a 3 M zinc oxide (ZnO) thin film (TF) prepared by the sol-gel spin-coating method. The ZnO thin film was deposited on a glass substrate using a 3 molar zinc acetate dihydrate precursor solution and subsequently annealed at 450 °C to achieve crystalline quality. Au NPs were decorated onto the ZnO surface via a colloidal drop-casting process followed by thermal treatment. Structural characterization by X-ray diffraction (XRD) confirmed the hexagonal wurtzite ZnO phase with a preferential c-axis orientation, while TEM and FESEM revealed uniformly distributed Au NPs (mean diameter ≈15–20 nm) on the ZnO film surface. UV-visible spectroscopy verified a distinct localized surface plasmon resonance (LSPR) absorption band centred near 530 nm arising from the Au NPs. The fabricated metal-semiconductor-metal (MSM) PD with Au NP decoration exhibited a responsivity of ≈62 A/W, a specific detectivity of ≈2.8×10¹² Jones, and an Iph/Idark ratio exceeding 10³ under 365 nm UV illumination (1 mW/cm²), representing improvements of approximately 4×, 3.5×, and two orders of magnitude over the bare ZnO device. The enhancement is attributed to synergistic LSPR-induced hot-electron injection, local field amplification, and Schottky barrier formation at the Au/ZnO interface. These results demonstrate Au NP integration on 3 M ZnO TFs as a cost-effective strategy for high-performance UV photodetection.

Ultraviolet photodetector; gold nanoparticles; ZnO thin film; localized surface plasmon resonance; Schottky barrier; sol-gel; responsivity; detectivity

1. H. Zhang, Y. Zhao, X. Geng, Y. Huang, Y. Li, H. Liu, Y. Liu, Y. Li, X.-F. Wang, H. Tian, and R. Liang, "Au nanoparticles-decorated surface plasmon enhanced ZnO nanorods ultraviolet photodetector on flexible transparent mica substrate," IEEE J. Electron Devices Soc., vol. 7, pp. 196–202, 2019, doi: 10.1109/JEDS.2018.2889888. [Google Scholar] [Crossref]

2. Y. Jin, S. Jiao, H. Lu, D. Wang, S. Gao, and J. Wang, "Localized surface plasmon-enhanced ultraviolet and visible photoresponse based on ZnO films with Au nanoparticles," J. Electron. Mater., vol. 49, no. 8, pp. 4491–4497, Aug. 2020, doi: 10.1007/S11664-020-08153-3. [Google Scholar] [Crossref]

3. N. Gogurla, A. K. Sinha, S. Santra, S. Manna, and S. K. Ray, "Multifunctional Au-ZnO plasmonic nanostructures for enhanced UV photodetector and room temperature NO sensing devices," Sci. Rep., vol. 4, no. 1, p. 6483, 2015, doi: 10.1038/SREP06483. [Google Scholar] [Crossref]

4. J. D. Hwang, M. J. Lai, H.-Z. Chen, and M.-C. Kao, "Au-mediated surface plasmon enhanced ultraviolet response of p-Si/n-ZnO nanorods photodetectors," IEEE Photon. Technol. Lett., vol. 26, no. 10, pp. 1023–1026, May 2014, doi: 10.1109/LPT.2014.2312734. [Google Scholar] [Crossref]

5. A. Rajan, H. K. Yadav, V. Gupta, and M. Tomar, "Plasmonic enhancement of optical absorption of UV radiation by Au nanoparticles dispersed on ZnO thin film," Appl. Phys. A, vol. 116, no. 3, pp. 913–919, 2014, doi: 10.1007/S00339-014-8462-8. [Google Scholar] [Crossref]

6. Y.-L. Chu, Y.-H. Liu, T.-T. Chu, and S.-J. Young, "Improved UV-sensing of Au-decorated ZnO nanostructure MSM photodetectors," IEEE Sens. J., vol. 22, no. 6, pp. 5644–5650, Mar. 2022, doi: 10.1109/jsen.2022.3150254. [Google Scholar] [Crossref]

7. J. D. Hwang, F.-H. Wang, C.-Y. Kung, and M. C. Chan, "Using the surface plasmon resonance of Au nanoparticles to enhance ultraviolet response of ZnO nanorods-based Schottky-barrier photodetectors," IEEE Trans. Nanotechnol., vol. 14, no. 2, pp. 318–321, Jan. 2015, doi: 10.1109/TNANO.2015.2393877. [Google Scholar] [Crossref]

8. S. Debnath, S. Ghosal, M. Meyyappan, and P. K. Giri, "A fully-printed plasmonic nanoparticle-incorporated ZnO-based UV photodetector with very high responsivity and fast response," Flex. Print. Electron., 2024, doi: 10.1088/2058-8585/ad6332. [Google Scholar] [Crossref]

9. A. Rajan, A. Paliwal, V. Gupta, and M. Tomar, "Plasmonic enhancement of optical absorption of UV radiation in ZnO thin film based ultraviolet photodetectors," MRS Proc., vol. 1509, no. 1, pp. 1–6, 2013, doi: 10.1557/OPL.2013.352. [Google Scholar] [Crossref]

10. "The gold nanoparticles enhanced ZnO/GaN UV detector," IEEE J. Electron Devices Soc., vol. 10, pp. 847–853, 2022, doi: 10.1109/jeds.2022.3212395. [Google Scholar] [Crossref]

11. C.-S. Lin, X. Du, and W.-C. Lin, "High photoresponse of gold nanorods/zinc oxide photodetector using localised surface plasmon resonance," Sens. Actuators A, Phys., vol. 326, p. 112714, Aug. 2021, doi: 10.1016/J.SNA.2021.112714. [Google Scholar] [Crossref]

12. A. Rajan, K. Arora, B. Vidhani, J. Dalal, and P. Kumar, "Au-modified ZnO thin films for higher-performance ultraviolet photodetectors," RSC Adv., vol. 15, pp. 49728–49738, 2025, doi: 10.1039/d5ra08186f. [Google Scholar] [Crossref]

13. A. Bilgaiyan, T. Dixit, I. A. Palani, and V. Singh, "Performance improvement of ZnO/P3HT hybrid UV photo-detector by interfacial Au nanolayer," Phys. E Low-Dimens. Syst. Nanostruct., vol. 86, pp. 136–141, Feb. 2017, doi: 10.1016/J.PHYSE.2016.07.010. [Google Scholar] [Crossref]

14. Z. Jin, L. Gao, Q. Zhou, and J. Wang, "High-performance flexible ultraviolet photoconductors based on solution-processed ultrathin ZnO/Au nanoparticle composite films," Sci. Rep., vol. 4, no. 1, p. 4268, 2015, doi: 10.1038/SREP04268. [Google Scholar] [Crossref]

15. Q. Li, J. Huang, J. Meng, and Z. Li, "Enhanced performance of a self-powered ZnO photodetector by coupling LSPR-inspired pyro-phototronic effect and piezo-phototronic effect," Adv. Opt. Mater., vol. 10, no. 7, p. 2102468, Jan. 2022, doi: 10.1002/adom.202102468. [Google Scholar] [Crossref]

16. G. Li, Q. Yan, X. Zhao, and Y. He, "The influence of surface processing on the surface plasmonic enhancement of an Al-nanoparticles-enhanced ZnO UV photodetector," Nanomaterials, vol. 13, no. 12, p. 1877, Jun. 2023, doi: 10.3390/nano13121877. [Google Scholar] [Crossref]

17. G. Shang, L. Tang, G. Wu, S. Yuan, M. Jia, X. Guo, X. Zheng, W. Wang, B. Yue, and K. S. Teng, "High-performance NiO/TiO2/ZnO photovoltaic UV detector," Sensors, vol. 23, no. 5, p. 2741, Mar. 2023, doi: 10.3390/s23052741. [Google Scholar] [Crossref]

18. N. Wang, J. Li, C. Wang, X. Zhang, S. Ding, Z. Guo, Y. Duan, and D. Jiang, "Improved UV photoresponse performance of ZnO nanowire array photodetector via effective Pt nanoparticle coupling," Nanomaterials, vol. 14, no. 17, p. 1442, Sep. 2024, doi: 10.3390/nano14171442. [Google Scholar] [Crossref]

19. I. B. Elkamel, N. Hamdaoui, A. Mezni, R. Ajjel, and L. Beji, "Photodetectors for weak signal conditions from Au/Cu co-doped ZnO," Opt. Quantum Electron., vol. 53, no. 7, pp. 1–14, Apr. 2021, doi: 10.21203/RS.3.RS-331709/V1. [Google Scholar] [Crossref]

20. C.-S. Lin and W.-C. Lin, "Development of high photosensitive gold nanorods/zinc oxide photodetector," vol. 20, pp. 77–81, Sep. 2021. [Google Scholar] [Crossref]