The influence of drift fields in thin silicon solar cells

Abstract

The influence of electric "drift" fields in the base of silicon solar cells on device performance is investigated. The drift fields are the result of a nonuniform dopant density in the base material. Numerical modelling is carried out for a range of representative cell structures and two different models for the dependence of the minority carrier lifetime on the dopant density. The cell design variables, in particular the dopant densities and the thicknesses of the device regions, are optimized with respect to the cell efficiency. Comparison of optimized cells incorporating a drift field with those not having a drift field, shows that a drift field can offer only small efficiency advantages for particular cell structures and recombination parameters, and only if large variations in dopant concentration can be achieved. Show more