Extracting high electrical currents with large fill factors from core/shell silicon nanopillar solar cells

Abstract

Although it is possible to improve the optoelectronic conversions of solar cells through the construction of one-dimensional nanostructures on their front surfaces, much effort at such fabrication has led to only modest increases in conversion efficiencies. In this study, we employed i-line lithography and ion implantation to fabricate arrays of well-aligned, contamination-free silicon nanopillars with core/shell p–n junctions for use in high-performance nanostructured solar cells. Such structures provided concurrent improvements in both the optical and electrical characteristics of nanopillar devices. We extracted high currents with large fill factors from these lowly reflective nanopillar arrays, resulting in power conversion efficiencies of up to 11.70 ± 0.22%—that is, 28% higher than that of the planar counterpart. Moreover, when applying 75-nm-thick silicon nitride as a passivation layer on the nanopillars, the average total reflection over wavelengths in the range of 400–1020 nm decreased to 2.56%, while the power conversion efficiency increased further to 12.39%.