The photoelectric effect is the production of electrons that are released when a photon is absorbed by a material. The photoelectric effect converts the photon energy in to ejected electrons. These electrons will drift within the material in any direction. In order to produce usable electric current, the electrons need to all move in one direction. This is accomplished with diode. A diode is made from two types of silicon sandwiched together that create an internal electric field. This electric field pulls the electrons to flow in one direction only. The flow of electrons in one direction creates current that we use.