Eur. Phys. J. B (2014) 87: 101
https://doi.org/10.1140/epjb/e2014-50129-x

Regular Article

Stochastic resonance of charge carriers diffusing in a nonhomogeneous medium with nonhomogeneous temperature

Department of Physics, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia

^a e-mail: ytatek@gmail.com

Received: 26 February 2014
Published online: 1 May 2014

Abstract

We investigate the dynamics of charge carriers hopping from one trap to the other trap along an n-type semiconductor layer consisting of a spatially nonhomogeneous trap distribution of depth Φ assisted by thermal noise. The trap profile is denser at the center and decays as one moves outward. In presence of a uniform background temperature, the charge carriers tend to accumulate around the center. Moreover, applying a nonhomogeneous temperature which is hot at the location of the maximum of trap density, results in a new redistribution of charge carriers which pile up around two points symmetrically positioned with respect to the center of the semiconductor layer making the system to behave like a bistable potential. The thermally activated rate of hopping of charge carriers as a function of the model parameters is studied in the high barrier limit. Using the two-state approximation, the stochastic resonance (SR) of the charge carriers dynamics in the presence of time varying external signal is also investigated.