charge-carrier saturation regime, the current through the sample is given by, where is the effective density of states of the charge carrier type in the semiconductor. Shot noise Space charge tends to reduce shot noise. Shot noise results from the random arrivals of discrete charge; the statistical variation in the arrivals produces shot noise. A space charge develops a potential that slows the carriers down. For example, an electron approaching a cloud of other electrons will slow down due to the repulsive force. The slowing carriers also increases the space charge density and resulting potential. In addition, the potential developed by the space charge can reduce the number of carriers emitted. When the space charge limits the current, the random arrivals of the carriers are smoothed out; the reduced variation results in less shot noise. See also Thermionic emission Vacuum tube Grid leak References Electricity Theories Microwave technology Vacuum tubes Mass spectrometry Semiconductors