How Everything Works
How Everything Works How Everything Works

Question 945

How do you make solar cells? — BP
Solar cells are made in the same way that semiconductor diodes are made. Two different types of semiconductor, p-type and n-type, are joined together to form a diode—a one-way device for electric current. When light energy is absorbed in the n-type portion of the diode, it can propel an electron across the p-n junction between the materials and into the p-type material. Since the electron can't return across the p-n junction to its original location, it must flow through an external circuit to get back. Since it obtains energy from the light that sent it across the junction, the electron can provide that energy to the circuit. The solar cell is thus a source of electric power.

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