## 3 Testing and Analysis
### Raman Scattering Spectroscopy and Raman Mapping
It would be an enhancement for the samples using the peak area divided by the concentration of bisphenol A ethoxylate (BPE). Furthermore, the concentration is \(10^{-6}\). As a result of this, the enhancement is shown in Table 4.  
Table 5 shows the EF for pH 9 samples and pH 10 samples. The EF of pH 9 (best- HQ) arrives at 2.07 \(\times\) 10\({}^{4}\). For Raman spectroscopy, this is quite a high enhancement. As for the EF pH 10, it would be a low enhancement. Hence, the influence of pH in the HCD for ZnO with silver is critical for enhancement. In XRD data could reveal the ZnO crystal at pH 9, too. So, the complete ZnO crystal is an important thing in this research. Furthermore, it should be controlled at pH 9 in this kind of experiment to obtain a good nanowire for Ag nanorod growth. In this project, we investigated which pH of ammonia is ideal for making good ZnO nanowires using HCD as a substrate of silver SERS substrates. In the XRD curve, a single diffraction peak (002) appeared in the sample with a ZnO preparation heating time of 4 h and a pH of 9. In the SEM test, the PH9 sample is also a uniform nanoarray that can produce the best hexagonal wurtzite structure. It can be seen that the growth structure,  
Figure 6: 1606 cm\({}^{-1}\) line Raman map, ZnO (pH10)/15 nm Cr/450 nm Ag nominal thickness (87 GLAD). Figure 7: Raman spectroscopy on the position (micrometres) = \(-9369\)\(\mu\)m, \(-3718\)\(\mu\)m, point #56.  
orientation and growth direction of ZnO nanoarrays are important factors affecting the Raman enhancement effect. The best surface-enhanced Raman scattering substrate can be prepared by ZnO nanoarrays with high orientation and appropriate porosity. Figure 8 was shown to express the spectra for different Ph. Comparing the spectral response spectra, the differences of zinc oxide films prepared with different pH levels can also be observed, so that the magnitude of the Raman enhancement effect can be judged according to its characteristics. For the preparation of ZnO nanoarrays, the method of hydrothermal evaporation was adopted in this paper, and the height and morphology of the nanoarrays were controlled by adjusting the pH. Compared with other advanced deposition methods, it not only effectively improves its enhancement factor, but also realises the control of strength to a certain extent. It has potential applications in medical, drug delivery, photothermal heat generation, photodetection, light harvesting, photocatalysis, agricultural and anti-drug fields. Its discrimination of different materials can be tuned by the way it controls the strength of reinforcement. However, to obtain nanorods with higher thicknesses, other deposition methods need to be tried. For example, the reactive deposition method realized by the cathode sputtering method uses a metal Zn target, which is filled with a mixed gas of argon and oxygen to make reactive sputtering, and its thickness is controlled by an optical film thickness control system [39]. Figure 8: Spectral response spectra of ZnO films prepared at different pH values and only Ag nanoarrays. \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **1595 cm\({}^{-1}\)** & **[BPE]** & **Enhancement Factor** \\ \hline BPE on Ag & 77.199 & \(1.0\times 10^{-4}\) & \(1\) \\ pH 9 (best-HQ) & 15,943.736 & \(1.0\times 10^{-6}\) & \(2.07\times 10^{4}\) \\ pH 9 (100) & 14,614.031 & \(1.0\times 10^{-6}\) & \(1.89\times 10^{4}\) \\ pH 9 (100) average & 1421.111 & \(1.0\times 10^{-6}\) & \(1.84\times 10^{3}\) \\ pH 9 (100) variance & 686.772 & \(1.0\times 10^{-6}\) & \(8.90\times 10^{2}\) \\ pH 10 & 3712.618 & \(1.0\times 10^{-6}\) & \(4.81\times 10^{3}\) \\ pH 10 average & 1761.464 & \(1.0\times 10^{-6}\) & \(2.28\times 10^{3}\) \\ pH 10 variance & 694.645 & \(1.0\times 10^{-6}\) & \(9.00\times 10^{2}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Enhancement calculation for the Raman enhancement substrate at different pH.