The Mechanism and Quantitative Description of the Photoconductivity and Photo-EPR in Beta-rhombohedral Boron Single Crystals at 77 K

Abstract

The inhomogeneous excitation resulting from strong absorption of the incident light as well as the low carrier mobility resulting in nearly negligible diffusion is taken into account in converting the directly measured conductance and number of spins into a time- and intensity of illuminationdependence of the concentrations of localized states and carriers. Then a model as simple as possible is searched out which will be able to explain simultaneously the behaviour of the conductivity and density of carriers and spin carrying centres. The resulting four coupled nonlinear differential equations have been solved analytically and numerically. Within the accuracy of the measurements, the observations can be reproduced.