Nanowire array photovoltaics: Radial disorder versus design for optimal efficiency

Solar cell designs based on disordered nanostructures tend to have higher efficiencies than structures with uniform absorbers, though the reason is poorly understood. To resolve this, we use a semi-analytic approach to determine the physical mechanism leading to enhanced efficiency in arrays containing nanowires with a variety of radii. We use our findings to systematically design arrays that outperform randomly composed structures. An ultimate efficiency of 23.75% is achieved with an array containing 30% silicon, an increase of almost 10% over a homogeneous film of equal thickness.
Comment: The following article appeared in Appl. Phys. Lett. Copyright 2012 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics