A p-n junction diode in which carrier storage is the major factor contributing to the operation of the device. The diode is designed so that most of the injected minority carriers under forward bias are stored near the junction and are immediately available for conduction when reverse bias is applied. When the diode is switched from forward to reverse bias the diode conducts in the reverse direction for a short time interval then the current is abruptly cut off when all the stored charges have been dispelled. The diode therefore remains in a low-impedance state until the cut-off occurs. The reverse voltage then builds up rapidly at a rate determined by the reverse junction capacitance and the external circuit. The cut-off occurs in the range of picoseconds and results in a fast-rising voltage wavefront that is rich in harmonics. The diode is therefore used as a harmonic generator or as a pulse former.

Most step-recovery diodes are fabricated in silicon with relatively long minority-carrier lifetimes ranging from 0.5 to 5 microseconds. Compare fast-recovery diode.