Effect of nonlinear physical phenomena on the photovoltaic effect in silicon p +–n–n + solar cells

Abstract

The influence of the combined effects of high injection level and heavy doping on the characteristics of silicon p +–n–n + solar cells is examined. The total amount of nonlinear physical phenomena (Auger recombination, electron-hole scattering, band-gap narrowing, charge carrier lifetime and transport coefficient reduction in the heavily doped layers of the structure) is taken into account. It has been established that a combined process which includes the generated charge carrier overflowing from n-base layer to highly doped n +-type and p +-type layers of the structure and their subsequent recombination in these highly doped layers, proves to be of great importance in silicon solar cells. The influence of electron-hole scattering on charge carrier transport in the highly doped n +-type and p +-type layers has been investigated for the first time. It has been found that minority carrier complete drag phenomenon results in a significant decrease of n +-type and p +-type layer saturation currents.