## 2 Design and Fabrication
### Technology Used for Photovoltaic Cells Fabrication  
The manufacturing technology that was used for the PV cell structures included four levels of masking: mask M1, which was used to obtain the textured surface of the structure, mask M2, which was used to obtain an active area n+ diffusion, mask M3, which was used for pre-contact/collection electrodes, and mask M4, which was used for the metal contacts. The overlap of these masks was controlled using a group of alignment signs that were located on the diagonal of the plate at a distance of 5 cm to the primary alignment cross. An image of the silica wafer with the photovoltaic cells before separation is presented in Figure 4. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
\begin{tabular}{c} **Nr.** \\ **CS** \\ \end{tabular} & \multicolumn{2}{c}{**without Resin Coverage**} & \multicolumn{2}{c}{**With Resin Coverage**} \\ \hline \multicolumn{1}{c}{} & & \multicolumn{2}{c}{**Type of Resin**} & \multicolumn{2}{c}{**100 Cycles (c)**} & \multicolumn{2}{c}{**UV**} \\  & & & \multicolumn{2}{c}{\(-20\)\({}^{\circ}\)**C + 60\({}^{\circ}\)C**} & \multicolumn{2}{c}{**3 Cycles of 20 min/c**} \\ \hline \multicolumn{1}{c}{} & V\({}_{\text{oc}}\) (mV) & I\({}_{\text{sc}}\) (mA) & \multicolumn{2}{c}{V\({}_{\text{oc}}\) (mV)} & I\({}_{\text{sc}}\) (mA) & V\({}_{\text{oc}}\) (mV) & I\({}_{\text{sc}}\) (mA) \\
1 & 430 & 4.5 & HT2 & 422 & 4.5 & 422 & 4.30 \\
2 & 450 & 4.4 & HP E40D & 440 & 3.87 & 443 & 3.51 \\
3 & 450 & 4.95 & HP E65 L & 480 & 5 & 456 & 4.59 \\
4 & 450 & 4.68 & HP E120 WSM-315 & 458 & 4.3 & 452 & 3.75 \\
5 & 430 & 4.96 & HP E45 KL & 443 & 4.2 & 439 & 3.75 \\
6 & 410 & 4.23 & HP E25 DM & 432 & 3.56 & 437 & 3.20 \\
7 & 453 & 5.3 & SIKA BIRESIN CR122 & 440 & 4.5 & 472 & 3.98 \\
8 & 430 & 4.84 & HP E25 DM & 440 & 4.3 & 448 & 3.72 \\
9 & 450 & 5 & HT2 & 456 & 4.8 & 461 & 4.18 \\
10 & 434 & 5 & EP 210 & 441 & 4.2 & 447 & 3.77 \\
11 & 450 & 4.7 & HP E120 WSM-315 & 472 & 4.7 & 462 & 4.30 \\
12 & 470 & 5.2 & HP E60 K & 456 & 4.6 & 470 & 4.21 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Main parameters of the photovoltaic cells measured before and after the mechano-climatic tests. Legend: 100 thermal cycles \(-20\)\({}^{\circ}\)C to \(+60\)\({}^{\circ}\)C and 3 cycles UV exposure 20 min each: c—number of cycles, T—temperature exposure, UV—ultraviolet exposure. Based on the mechanical and optical properties, the epoxy resin that was selected was HT 2, (produced by R&G Faserverbundwerstoffe GmbH, 71111 Waldenbuch, Germany). Figure 4: The silica wafer with photovoltaic cells before separation. The micro-texturing of the active surface in order to reduce the reflection losses at the radiation incident surface was performed by a photolithographic process through the oxide mask realised after the diffusion of boron. An image of the pyramids obtained on the surface of photovoltaic cells is presented in Figure 5.  
Technological process of photovoltaic cell fabrication is presented in Figure 6.  
The classic wing manufacturing technology that has been used so far does not allow for the integration of photovoltaic cells, which there is a high probability of during vacuuming due to the pressure exerted on the photovoltaic cells, causing them to exceed the maximum allowable deformation on the areas where the curvature of the wing is greater than 0.5 mm. Following the research and studies that have previously been performed, the necessary changes in the technological process were determined in order to ensure the integration of the cells in the wing without destroying them. The wing lamination would be conducted in two distinct stages:  
1. Embedding the cells in resin support;
2. Lamination of the resistance structure (carbon fiber in resin support).