Light Trapping in Silicon Nanowire Solar Cells
Top Cited Papers
- 28 January 2010
- journal article
- letter
- Published by American Chemical Society (ACS) in Nano Letters
- Vol. 10 (3), 1082-1087
- https://doi.org/10.1021/nl100161z
Abstract
Thin-film structures can reduce the cost of solar power by using inexpensive substrates and a lower quantity and quality of semiconductor material. However, the resulting short optical path length and minority carrier diffusion length necessitates either a high absorption coefficient or excellent light trapping. Semiconducting nanowire arrays have already been shown to have low reflective losses compared to planar semiconductors, but their light-trapping properties have not been measured. Using optical transmission and photocurrent measurements on thin silicon films, we demonstrate that ordered arrays of silicon nanowires increase the path length of incident solar radiation by up to a factor of 73. This extraordinary light-trapping path length enhancement factor is above the randomized scattering (Lambertian) limit (2n2 ∼ 25 without a back reflector) and is superior to other light-trapping methods. By changing the silicon film thickness and nanowire length, we show that there is a competition between improved absorption and increased surface recombination; for nanowire arrays fabricated from 8 μm thick silicon films, the enhanced absorption can dominate over surface recombination, even without any surface passivation. These nanowire devices give efficiencies above 5%, with short-circuit photocurrents higher than planar control samples.Keywords
This publication has 21 references indexed in Scilit:
- Dopant profiling and surface analysis of silicon nanowires using capacitance–voltage measurementsNature Nanotechnology, 2009
- Wafer-scale silicon nanopillars and nanocones by Langmuir–Blodgett assembly and etchingApplied Physics Letters, 2008
- Silicon Nanowire Radial p−n Junction Solar CellsJournal of the American Chemical Society, 2008
- Coaxial silicon nanowires as solar cells and nanoelectronic power sourcesNature, 2007
- Comparison of the device physics principles of planar and radial p-n junction nanorod solar cellsJournal of Applied Physics, 2005
- Crystalline silicon on glass (CSG) thin-film solar cell modulesSolar Energy, 2004
- Recent developments in photovoltaicsSolar Energy, 2004
- Energy pay-back time and CO2 emissions of PV systemsProgress In Photovoltaics, 2000
- Preparation of monodisperse silica particles: Control of size and mass fractionJournal of Non-Crystalline Solids, 1988
- Modelling of minority-carrier transport in heavily doped silicon emittersSolid-State Electronics, 1987