A new injection pulse phenomenon is reported which may have a variety of applications including the detection of infrared (IR) radiation. Injection current pulses were observed in simple circuits containing forward biased siliconp‐i‐ndiodes at liquid‐helium temperatures. Under exposure to IR radiation, the pulse rate was observed to increase approximately linearly with increasing incident IR intensity. The substantial voltage, current, and power output may eliminate the need for on‐chip amplifiers in many applications. Figures of merit are discussed, although the performance of the devices has not yet been optimized.