Light induced change on the built-in potential of p/p+ structures and its effect on carrier lifetime measurements

This paper presents an analytical expression for the built-in potential in epitaxial p/p+ structures as a function of the light generated carrier concentration. The expression is based on the use of the injection relation whose validity is critically discussed. Moreover, we calculate the effective carrier lifetime from the current continuity equation. The expression for the built-in potential is taken into account in the boundary conditions, which allows us to study the influence of the built-in potential on the effective carrier lifetime. Analytical solutions are verified with numerical simulations.