Photovoltaic cell manufacturing. Rack of polycrystalline silicon wafers being placed in a deposition furnace (background) during the manufacturing process for photovoltaic cells. Photovoltaic cells, the basic components of solar panels, contain silicon, a semiconductor material that can absorb energy from sunlight and convert it into an electrical current. Several layers are deposited on the silicon wafer during its production. Part of the process involves the high-temperature thermal diffusion of phosphorus (P) derived from phosphorus oxychloride (POCl3).