What is the construction of a Solar Cell? How is EMF generated? - Electronics

What is the construction of a Solar Cell? How is EMF generated?

The construction is explained as follows-

-A Silicon or Germanium p-n junction diode packed in a can with a glass window on the top.

-A p-Silicon wafer of about 300 micrometer is taken over which a thin layer (about 0.3 micrometer) is grown on one side.

-The other side is coated with a metal. This acts as a “Back Contact”.

-On top of the n-Silicon layer, a metal finger electrode is deposited. This acts as a “Front Contact”.

The EMF is generated as-

-Photons having energy greater than threshold energy (i.e. the energy gap) generate electron-hole pairs.

-The electron-hole pairs get separated due to the electric field in the depletion region.

-Electrons reaching the n-region get collected by the front contact while the holes reaching the p-region are collected by the back contact.

-Thus, due to the charge accumulation, an EMF is generated.