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Published July 2012 | public
Journal Article

Wafer-Scale Growth of Silicon Microwire Arrays for Photovoltaics and Solar Fuel Generation


Silicon microwire arrays have recently demonstrated their potential for low-cost, high-efficiency photovoltaics and photoelectrochemical fuel generation. A remaining challenge to making this technology commercially viable is scaling up of microwirearray growth. We discuss here a technique for vapor–liquid–solid growth of microwire arrays on the scale of six-inch wafers using a cold-wall radio-frequency heated chemical vapor deposition furnace, enabling fairly uniform growth over large areas with rapid cycle time and improved run-to-run reproducibility. We have also developed a technique to embed these large-area wire arrays in polymer and to peel them intact from the growth substrate, which could enable lightweight, flexible solar cells with efficiencies as high as multicrystalline Si solar cells. We characterize these large-area microwire arrays using scanning electronmicroscopy and confocal microscopy to assess their structure and fidelity, and we test their energy-conversion properties using a methyl viologen (MV^(2+/+) ) liquid junction contact in a photoelectrochemical cell. Initial photoelectrochemical conversion efficiencies suggest that the material quality of these microwire arrays is similar to smaller (∼1 cm^2 ) wire arrays that we have grown in the past, indicating that this technique is a viable way to scale up microwire-array devices.

Additional Information

© 2012 IEEE. Manuscript received July 11, 2011; revised March 7, 2012; accepted March 19, 2012. Date of publication April 19, 2012; date of current version June 18, 2012. This work was supported in part by the Defense Advanced Research Projects Agency under Contract W911NF-09-2-0011 and in part by the U.S. Department of Energy under Grant DE-FG02-05ER15754. The authors would like to thank A. Leenheer for assistance with confocal microscopy measurements. Facilities for wafer preparation were provided by the Kavli Nanoscience Institute at Caltech. D. B. Turner-Evans acknowledges support from a National Science Foundation graduate fellowship.

Additional details

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