A detector in which the voltage changes in response to incident radiation. In a simple p–n semiconductor junction, incident radiation leads to a flow of current over the junction, and the device acts as a photoconductive detector. But if the diode is in series with a very high resistance, the voltage across that resistance changes with the intensity of the incoming radiation, so that the diode then acts as a photovoltaic detector. Various semiconductor materials such as silicon, indium antimonide, and gallium arsenide can be used for the detectors. They can operate from visual wavelengths to 10 μm or longer.
Subjects: Astronomy and Astrophysics.