Photoeffects in Nonuniformly Irradiated p‐n Junctions

A theoretical basis is provided for the interpretation of photoeffects observed in nonuniformly irradiated p‐n junctions. Differential equations describing the junction photovoltage are developed through an application of the continuity and diffusion equations. Solutions of the small‐signal steady‐state photoeffect equation indicate that the effects of nonuniform irradiation become increasingly important as the ratio of the lateral to the transverse resistance increases. α, a parameter introduced in this paper and designated as the lateral‐fall off parameter, is a measure of this resistance ratio. The lateral photovoltage resulting from nonuniform irradiation can be eliminated by reverse biasing the junction into saturation. Experimental curves in agreement with the predictions of the analysis are presented.