## 4 Results and Discussion  
To maximize the absorbed light in the visible and NIR regions, which leads to an increase in the \(J_{\rm{sc}}\) and the overall frequency, different proposals will be produced. The absorption of a traditional SiNW solar cell will be compared to SiNWs coated with a 2D graphene layer and with/without Au plasmonic nanoparticles distributed on the silicon substrate layer. Figure 2a,b illustrates the absorption and transmission of the four proposed techniques. As shown in Figure 2a, the absorptions of the traditional SiNWs and of SiNWs coated with graphene are almost the same; however, a high absorption has been obtained when Au NPs are distributed on the top silicon substrate surface. The light transmitted through the solar cell is illustrated given in Figure 2b. However, it is very hard to distinguish \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Material** & **Term** & **Strength** & **Plasma Frequency** & **Resonant Frequency** & **Damping Frequency** \\ \hline \multirow{4}{*}{Ag} & 0 & 0.8450 & 0.136884 \(\times\) 10\({}^{+17}\) & 0.00000 \(\times\) 10\({}^{+00}\) & 0.729239 \(\times\) 10\({}^{+14}\) \\  & 1 & 0.0650 & 0.136884 \(\times\) 10\({}^{+17}\) & 0.123971 \(\times\) 10\({}^{+16}\) & 0.590380 \(\times\) 10\({}^{+16}\) \\  & 2 & 0.1240 & 0.136884 \(\times\) 10\({}^{+17}\) & 0.680775 \(\times\) 10\({}^{+16}\) & 0.686701 \(\times\) 10\({}^{+15}\) \\  & 3 & 0.0110 & 0.136884 \(\times\) 10\({}^{+17}\) & 0.124351 \(\times\) 10\({}^{+17}\) & 0.987512 \(\times\) 10\({}^{+14}\) \\  & 4 & 0.8400 & 0.136884 \(\times\) 10\({}^{+17}\) & 0.137993 \(\times\) 10\({}^{+17}\) & 0.139163 \(\times\) 10\({}^{+16}\) \\  & 5 & 5.6460 & 0.136884 \(\times\) 10\({}^{+17}\) & 0.308256 \(\times\) 10\({}^{+17}\) & 0.367506 \(\times\) 10\({}^{+16}\) \\ \hline \multirow{4}{*}{Au} & 0 & 0.7600 & 0.137188 \(\times\) 10\({}^{+17}\) & 0.000000 \(\times\) 10\({}^{+00}\) & 0.805202 \(\times\) 10\({}^{+14}\) \\  & 1 & 0.0240 & 0.137188 \(\times\) 10\({}^{+17}\) & 0.630488 \(\times\) 10\({}^{+15}\) & 0.366139 \(\times\) 10\({}^{+15}\) \\  & 2 & 0.0100 & 0.137188 \(\times\) 10\({}^{+17}\) & 0.126098 \(\times\) 10\({}^{+16}\) & 0.524141 \(\times\) 10\({}^{+15}\) \\  & 3 & 0.0710 & 0.137188 \(\times\) 10\({}^{+17}\) & 0.451065 \(\times\) 10\({}^{+16}\) & 0.132175 \(\times\) 10\({}^{+16}\) \\  & 4 & 0.6010 & 0.137188 \(\times\) 10\({}^{+17}\) & 0.653885 \(\times\) 10\({}^{+16}\) & 0.378901 \(\times\) 10\({}^{+16}\) \\  & 5 & 4.3840 & 0.137188 \(\times\) 10\({}^{+17}\) & 0.202364 \(\times\) 10\({}^{+17}\) & 0.336362 \(\times\) 10\({}^{+16}\) \\ \hline \multirow{4}{*}{Cu} & 0 & 0.5750 & 0.164535 \(\times\) 10\({}^{+17}\) & 0.000000 \(\times\) 10\({}^{+00}\) & 0.455775 \(\times\) 10\({}^{+14}\) \\  & 1 & 0.0610 & 0.164535 \(\times\) 10\({}^{+17}\) & 0.442101 \(\times\) 10\({}^{+15}\) & 0.574276 \(\times\) 10\({}^{+15}\) \\  & 2 & 0.1040 & 0.164535 \(\times\) 10\({}^{+17}\) & 0.449242 \(\times\) 10\({}^{+16}\) & 0.160433 \(\times\) 10\({}^{+16}\) \\  & 3 & 0.7230 & 0.164535 \(\times\) 10\({}^{+17}\) & 0.805202 \(\times\) 10\({}^{+16}\) & 0.488135 \(\times\) 10\({}^{+16}\) \\  & 4 & 0.6380 & 0.164535 \(\times\) 10\({}^{+17}\) & 0.169852 \(\times\) 10\({}^{+17}\) & 0.654037 \(\times\) 10\({}^{+16}\) \\ \hline \multirow{4}{*}{Al} & 0 & 0.5230 & 0.227583 \(\times\) 10\({}^{+17}\) & 0.000000 \(\times\) 10\({}^{+00}\) & 0.714047 \(\times\) 10\({}^{+14}\) \\  & 1 & 0.2270 & 0.227583 \(\times\) 10\({}^{+17}\) & 0.246118 \(\times\) 10\({}^{+15}\) & 0.505910 \(\times\) 10\({}^{+15}\) \\ \cline{1-1}  & 2 & 0.0500 & 0.227583 \(\times\) 10\({}^{+17}\) & 0.234572 \(\times\) 10\({}^{+16}\) & 0.474006 \(\times\) 10\({}^{+15}\) \\ \cline{1-1}  & 3 & 0.1660 & 0.227583 \(\times\) 10\({}^{+17}\) & 0.274680 \(\times\) 10\({}^{+16}\) & 0.205251 \(\times\) 10\({}^{+16}\) \\ \cline{1-1}  & 4 & 0.0300 & 0.227583 \(\times\) 10\({}^{+17}\) & 0.527635 \(\times\) 10\({}^{+16}\) & 0.513810 \(\times\) 10\({}^{+16}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Plasmonic parameters used for the metallic nanoparticle.