Page 60 - Advances in Renewable Energies and Power Technologies
P. 60

4. The Solar Cells    33













































                  FIGURE 1.29
                  (A) Surface texturing and (B) effect of antireflective coating and texturing on the
                  reflectivity.




                     Wire attachment to the solar cells is made by soldering or welding. So, the metal-
                  lization of the solar cell must be matched to these assembly processes. In addition, it
                  must be corrosion resistive, adhere well to the Si, and form Ohmic contact with it. It
                  must also not diffuse or micro alloy with Si because the shallow junction can be
                  partially shorted. No single metal call satisfies all these requirements. Multi-layer
                  metallization is normally used:

                  1. Titanium (0.1 mm) þ silver (3e5 mm) (sensitive to humidity).
                  2. Ti (0.1 mm) þ Pd (20e50 nm) þ silver (3e5 mm) (protect against humidity).
                  3. Printed silver layer (25 mm).
                  4. (CrePdeAg) for space cells.
   55   56   57   58   59   60   61   62   63   64   65