Spectral Distribution of the Photomagnetoelectric Effect in Ge: Experiment

Abstract

The photomagnetoelectric effect has been studied in germanium as a function of the wavelength of incident radiation in the region from 0.5 to 2.0 microns. The dependence of both photoconductivity and photo-magnetoelectric (PME) response has been measured in various samples, using front and back surface recombination velocities and bulk recombination as parameters. It has been found that under certain conditions of bulk and surface recombination a reversal in sign for the PME response occurs over the frequency range studied. Sign reversals obtain at wavelength in the range from 1.55 to 1.85 microns, corresponding to partial optical transparency. The exact frequencies at which reversal occurs depend on the surface and bulk recombination rates, the condition being that the Dember field be zero corresponding to equal carrier concentrations on the front and back surfaces. Furthermore, the present observations are shown to be in good qualitative agreement with the theoretical work reported by G\"artner. Experimental procedures are described, and it is shown how this effect can be used to advantage in the study of surface recombination velocities in various environments.