Photovoltaic cells are made of semiconductors materials that include silicon (Si) which is a good insulator. To make silicon more conductive electrically, additives (impurities) are added like phosphorus (P) and boron (B). The phosphorous-silicon compound is called n-type and it is electrically neutral. Silicon can also be doped with boron, which is called p-type, which is also electrically neutral. When the n-type silicon is attached to the p-type silicon, they turn into a device known as diode or p–n junction. When the two types are attached, which is the main component of a photovoltaic cell.

There are two major types of photovoltaic cells: concentrating and flat-plate.

The construction of the solar cell requires several added components such as:

• cover glass
• antireflective coating
• connecting grid

Modules:  A single photovoltaic cell of 10 cm in diameter produces about 1 W power, which is enough to run a low-power calculator. Therefore, photovoltaic cells are connected in parallel and series. The parallel connection increases the overall current, and the series connection increases the overall voltage. When several photovoltaic cells are connected they form a module or panel and for higher power demand, several modules are connected together to form a photovoltaic array. More sophisticated photovoltaic arrays are mounted on tracking devices that follow the sun throughout the day. Several of these arrays form a photovoltaic system similar to the one shown below. When a large number of these arrays produce substantial power, they are often connected to the distribution or transmission system.