Conductivity support of AZO in enhancements of SERS Ag/AZO substrate to detect ketoprofen.

In this paper, the high-performance SERS substrate based on aluminum-doped zinc oxide (AZO) 98 wt% ZnO and 2 wt% Al₂O₃ film with Ag nanoparticles (NPs) is fabricated to detect the rhodamine 6G and ketoprofen standard at very low concentration. The AZO film is deposited on a glass platform by the DC magnetron sputtering method. Then Ag NPs with a high density of “hot spots” are decorated on the AZO film by the DC magnetron sputtering. The optical and electrical properties, structure, surface morphology, and element in the sample are investigated by ultraviolet-visible spectroscopy (UV–Vis), Hall measurement, Raman spectroscopy, scanning electron microscopy (SEM), X-Ray diffraction (XRD) and energy dispersion X-ray spectroscopy (EDS). The results illustrate the optimal SERS Ag (10 s)/AZO (45 min) substrate possessing good crystallinity, high carrier concentration, and rouge surface with the AZO grains average diameter of 100–140 nm, Ag NPs sizes of about 30–40 nm are evenly distributed throughout the sample surface. The sensitivity of Ag (10 s)/AZO (45 min) SERS is investigated using rhodamine 6G reagent. The Raman results show that Ag/AZO SERS substrate can detect rhodamine 6G with a limit of detection (LOD) of 10^{− 15} M and enhancement factor (EF) of ∼ 3.7 ⋅ 10¹⁴. The highly sensitive SERS substrate detects ketoprofen standards with a LOD of 0.01 ppm, and an EF of 6.7 ⋅ 10⁶. [ABSTRACT FROM AUTHOR]