Drift-diffusion modeling of a superlattice p-i-n device with resonant conduction-band assisted photon absorption and carrier

In this work we present a novel solar cell design exploiting the strong two photon absorption properties of highly electronically mismatched dilute nitride semiconductors. The superlattice design is expected to circumvent the poor minority carrier properties encountered in bulk materials. By aligning the upper E+ conduction band branch of the dilute nitride alloy with that of AlGaAs the upper band preserves its bulk nature thus facilitating the 2nd photon assisted promotion of carriers photo-generated at the intermediate level and avoids limitations imposed by inter-subband optical selection rules of 2D systems. Drift diffusion modeling results indicates possibility for attaining 1 sun efficiencies in excess of 31% AM0 and 36% AM1.5. Under concentrated sunlight conditions efficiencies in excess of 47% (1000X AM1.5 illumination) seem achievable.