Electron Barrier Engineering in a Thin-Film Intermediate-Band Solar Cell

Improved open-circuit voltages have been achieved in dilute nitride thin-film intermediate-band solar cells by optimizing intermediate-band barrier layers. The blocking properties of the AlGaAs electron barrier are found to critically depend on the barrier-doping level. Open-circuit voltages V_OC improved when electron-doping levels in the AlGaAs barriers were reduced. This is ascribed to the increased association of V_OC with the larger gap defined by the valence and conduction bands due to the improved electrical isolation of the intermediate band.