A Model for the Steady-State Photoconductance of an Abrupt p-n Junction Semiconductor Diode Assuming Flat Quasi-Fermi Levels

A theoretical model for the steady-state photoconductance of an abrupt p-n junction semiconductor diode is presented. It assumes one-dimensional geometry and flat quasi-Fermi levels (QFLs) and involves a numerical integration over electrostatic potential. The flat-QFL model permits the determination of the excess carrier concentration in both quasi-neutral regions from a measurement of a semiconductor's photoconductance, accounting for depletion-region modulation more accurately than its alternatives-particularly for thin samples and low-injection conditions. The model can be generalized to include variable carrier mobilities and to have different intrinsic carrier concentrations in n- and p-type layers