Multi-junction solar cell with schwachnitridischer part cell having a graded doping

A solar cell with an adjusted grid has a partial cell on Schwachnitridbasis with an exponentially extending doping for controlling the current-carrying function of the solar cell. More particularly, the disclosed solar cell with at least one dilute nitride has a variable doped base or a variably doped emitter. In one embodiment, the multi-junction solar cell has an upper subcell, a middle subcell, and a lower dilute nitride, wherein the lower dilute nitride having a doping of the base and / or of the emitter, which is at least partially doped to improve the characteristics of the solar cell characteristics with an exponential curve. In the structure of the dilute nitride may have the smallest band gap and a matched to the substrate lattice. The mean cell typically has a higher bandgap than the dilute nitride and at the same time is adapted to suit the dilute nitride lattice. The upper part of the cell typically has the largest band gap and an adapted to the adjacent sub-cell grid.