Nanowires could be solution for high-performance solar cells

November 11, 2011

Photovoltaic nanowires grown on a silicon substrate (credit: Xiuling Li)

University of Illinois researchers.have developed a way to integrate semiconductor nanowires on silicon wafers, which could help engineers realize high-performance solar cells and other electronics.

“III-V” semiconductors — used in photovoltaic cells — don’t integrate with silicon seamlessly, which is a problem, since silicon is the most ubiquitous electronics device platform.

So instead of a conventional thin film, the Illinois team grew a densely packed array of photovoltaic nanowires that grow up vertically from the silicon wafer. “The nanowire geometry offers a lot more freedom from lattice-matching restrictions by dissipating the mismatch strain energy laterally through the sidewalls,” electrical and computer engineering professor Xiuling Li said.

The nanowire geometry provides the additional benefit of enhancing solar cell performance through greater light absorption and carrier collection efficiency. The nanowire approach also uses less material than thin films, reducing the cost.

Ref.: Jae Cheol Shin, et al., InxGa1-xAs Nanowires on Silicon: One-Dimensional Heterogeneous Epitaxy, Bandgap Engineering, and Photovoltaics, Nano Letters, 2011; [DOI: 10.1021/nl202676b]