Page 73 - Applied Photovoltaics

3. Surface texturing can also be used to minimise reflection. Any ‘roughening’
of the surface reduces reflection by increasing the chances of reflected light
bouncing back onto the surface, rather than out to the surrounding air.
The surface of crystalline silicon can be textured uniformly by etching along
the faces of the crystal planes. The crystalline structure of silicon results in a
surface made up of pyramids, if the surface is appropriately aligned with
respect to the internal atoms (Chitre, 1978), as shown in Fig. 4.4. An electron
microscope photograph of a textured silicon surface is shown in Fig. 4.5.

Figure 4.4. A square based pyramid, which forms the surface of an appropriately-
textured crystalline silicon solar cell.

Figure 4.5. Scanning electron microscope image of a textured silicon surface.

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