Numerical study of surface charge effects on a p-n junction model system: Modulation of junction potential, band diagrams, and recombinations

Abstract

We theoretically investigate the surface charge effects on a p-n junction model system. It is calculated that the polarity of the surface charges around the junction interface induces different variations in the built-in potential, which has been demonstrated to affect the band diagrams of p-n junction systems. That is, the more negative the surface charge is, the more the built-in potential decreases, and vice versa for positive surface charges in the system. These surface charges affect the modulation of three recombination processes, i.e. the Shockley-Read-Hall, band-to-band, and Auger recombination processes, and are numerically investigated with different surface charge densities imposed at the junction interface. As a result, it is calculated that the three recombination rates are reduced with increasing magnitudes of surface charge density due to the free carrier depletion that occurs around the p-n junction regions.