Subbandgap current collection through the implementation of a doping superlattice solar cell

Abstract

The simulation and fabrication of a multi-period GaAs n-type/intrinsic/p-type/intrinsic (nipi) doping superlattice solar cell have been demonstrated. Devices have been fabricated and characterized, demonstrating a proof of concept for a nipi device contacted via epitaxial regrowth. Current-voltage measurements in the dark and under one sun illumination were simulated and measured experimentally. Efficient current collection was demonstrated with an integrated short circuit current of 23.24 mA/cm2 measured through spectral response. Efficiency improvements from prior results have been achieved, with a maximum one sun AM0 efficiency of 3.42%. Sub-bandgap spectral response shows a 3.3% increase over the bulk response.