Photovoltaic cell. Photovoltaic cells are made of a semiconductor such as silicon or gallium arsenide. The electrons in the semiconductor are only loosely bound to their atoms. These electrons can be liberated by the addition of energy. Electrons released by light energy are collected by the grid of wires which run over the cell's surface to make an electric current. The glove would be used in a 'clean room' to prevent contamination of the solar cell when handled.