Theory of the Photomagnetoelectric Effect in Semiconductors

Abstract

Results are obtained for the photomagnetoelectric (PME) effect that are more general and exact than those of earlier theory. Through an ambipolar treatment, the underlying general theory for current carrier transport with magnetic field, which can provide similarly unrestricted results for the Hall, Suhl, and magnetic rectifier effects, is first developed. The PME effect is considered in detail for the infinite slab with strongly absorbed steady radiation on one surface and parallel, steady, uniform magnetic field. Small Hall angles and constant surface recombination velocities and lifetime are assumed. Small-signal theory is given as well as nonlinear theory for arbitrary light intensity. The latter provides methods for determining lifetime that require only negligible dark-surface concentration of added carriers, as well as a method for determining surface recombination velocity; curves for these are given for germanium. Expressed in terms of conductance increase, PME current or voltage does not depend explicitly on light intensity nor on recombination velocity for the illuminated surface. Distance along the slab between equipotential probes on opposite surfaces as obtained from a nul measurement in which Dember and PME potentials cancel determines directly the sum of the magnitudes of the Hall angles, upon which the PME effect depends.