Injected Current Carrier Transport in a Semi-Infinite Semiconductor and the Determination of Lifetimes and Surface Recombination Velocities

Abstract

With both surface and volume recombination taken into account, time‐dependent and steady‐state Green's functions are obtained for a point source of added carriers in a semi‐infinite semiconductor, and for infinite line and plane sources parallel to the surface. Small‐signal theory is employed, and a compact Stieltjes‐integral derivation is given. The Green's functions are specialized to provide: the time dependence of surface concentration following the instantaneous injection of carriers at a point on the surface; that following instantaneous injection which is uniform over the surface; and the distance dependences for steady point, infinite‐line, semi‐infinite plane, and semi‐infinite line surface sources. Steady flows of minority carriers from these sources into a p—n junction perpendicular to the surface are also calculated. Analytical approximations are found for the steady‐source cases. Theoretical and experimental aspects of the determination of lifetimes and surface recombination velocities from data by means of these results are discussed.