Nonequilibrium charge carriers and linear galvanomagnetic phenomena in semiconductors

Abstract

In linear approximations using small electric Ex and magnetic Hy fields, nonequilibrium carriers appear in bounded semiconductors orthogonal to the electric field. An expression for the longitudinal magnetoresistance in a finite bipolar semiconductor is obtained by taking into account the redistribution of the nonequilibrium carriers along the z axis (thickness 2b), the generation and recombination processes assisted by traps (Shockley-Read model), and the different surface recombination velocities. For the first time, it is shown that the redistribution of nonequilibrium carriers generates a change in the conductivity from the classical value. In this case, two new terms appear, which depend on the thickness b. The first contribution to the magnetoresistance exhibits a linear dependence on the magnetic field, where the conductivity of the semiconductor increases or decreases depending on the magnetic field orientation. The second contribution shows a quadratic dependence on the magnetic field. The changes in current density in the cases of strong and weak recombination, and in the cases of intrinsic and extrinsic semiconductors, are also studied.