Response of a P-N junction to a linearly decreasing current

A study is made to determine analytically the time variation of the terminal voltage of a p-n junction in response to a terminal current which starts with a large forward value and continues to decrease linearly until the reverse saturation is attained. It is shown that the period between the reversal of current and the reversal of voltage depends exclusively on the lifetime, diffusion length, and thermal equilibrium densities of minority carriers in both regions of the junction. For some cases, the period between the reversal of current and voltage reduces to half the lifetime of either of the two types of minority carriers. This property allows measuring the lifetime of minority carriers for certain p-n junctions by relatively simple means.