Turn-on and turn-off voltages of an avalanche p—n junction

Characteristics of the turn-on and turn-off voltage of avalanche p-n junctions were demonstrated and studied. As opposed to existing reports, the differences between the turn-on and turn-off voltage cannot be neglected when the size of the p-n junction is in the order of microns. The difference increases inversely with the area of a junction, exerting significant influences on characterizing some parameters of devices composed of small avalanche junctions. Theoretical analyses show that the mechanism for the difference lies in the increase effect of the threshold multiplication factor at the turn-on voltage of a junction when the area of a junction decreases. Moreover, the "breakdown voltage" in the formula of the avalanche asymptotic current is, in essence, the avalanche turn-off voltage, and consequently, the traditional expression of the avalanche asymptotic current and the gain of a Geiger mode avalanche photodiode were modified. incorrect characterization of the device parameters and affect the practical applications of the device. In this study, experi- ments were conducted to gain an insight into mechanisms in order to account for large differences between Vturn-on and Voff for small p-n junctions and, furthermore, theoretical analyses were made to accurately determine the important parameters of a device.