3. Photovoltaic cells

3.1 Silicon cell

The silicon solar cell is a special large diode. If we try to capture light with a silicon crystal, we find that silicon reflects 30% of the light received.

This is due to the high refractive index of silicon (2 in the near infrared, 7 in the ultraviolet). This means that an anti-reflective layer must be added to the silicon surface to improve efficiency. It is also necessary to determine the depth in the crystal at which the junction should be fabricated to optimize yield.

• Photocurrent

  Illumination of a solar cell produces a proportional current called "photocurrent", independent of voltage. But as the voltage increases, part of this current is dispersed in the junction...