PROCEEDINGS ARTICLE | September 11, 2008
Proc. SPIE. 7047, Nanoscale Photonic and Cell Technologies for Photovoltaics
KEYWORDS: Semiconductors, Photovoltaics, Solar energy, Polymers, Solar cells, Silicon, Heterojunctions, Absorption, Nanorods, Nanowires
The use of semiconductor nanowires for photovoltaic applications is advantageous for several reasons: 1) it permits
interpenetrating networks of materials for semiconductor heterojunctions at the nanoscale, allowing efficient carrier
extraction following light absorption, 2) long absorption paths are possible while maintaining short distances for carrier
collection, even in imperfect materials, 3) single crystal materials can be grown in relatively thin films with little
material, 4) strong light trapping is possible due to the geometry of the nanowires, and 5) manipulation of materials
properties is possible by varying the size of the nanostructures. These advantages must be traded off against the
difficulties of fabricating devices (particularly planarization of structures), issues with recombination centers at
interfaces, and the requirement of making ohmic contacts with relatively low temperature processes. The optical and
electronic properties of semiconductor nanowires, nanowire arrays, and heterojunction interfaces are discussed. Recent
results for photovoltaic cells based on semiconductor nanorods and nanowires are summarized, and opportunities for
improvement of device characteristics are presented.
