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 microwire-array 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 electron microscopy and confocal microscopy to assess their structure and fidelity, and we test their energy-conversion properties using a methyl viologen (MV<formula formulatype="inline"><tex Notation="TeX">$^{2+/+}$</tex></formula>) 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<formula formulatype="inline"><tex Notation="TeX">$^2$</tex></formula>) wire arrays that we have grown in the past, indicating that this technique is a viable way to scale up microwire-array devices.

[1]  Nathan S. Lewis,et al.  High-performance Si microwire photovoltaics , 2011 .

[2]  N. Lewis,et al.  pH-Independent, 520 mV Open-Circuit Voltages of Si/Methyl Viologen 2+/+ Contacts Through Use of Radial n + p-Si Junction Microwire Array Photoelectrodes , 2011 .

[3]  Nathan S Lewis,et al.  Photoelectrochemical hydrogen evolution using Si microwire arrays. , 2011, Journal of the American Chemical Society.

[4]  M. H. van der Veen,et al.  Large‐area, catalyst‐free heteroepitaxy of InAs nanowires on Si by MOVPE , 2011 .

[5]  Zhongyi Guo,et al.  A waferscale Si wire solar cell using radial and bulk p–n junctions , 2010, Nanotechnology.

[6]  T. Mayer,et al.  Radial junction silicon wire array solar cells fabricated by gold-catalyzed vapor-liquid-solid growth , 2010 .

[7]  Wenzhuo Wu,et al.  Wafer-scale high-throughput ordered growth of vertically aligned ZnO nanowire arrays. , 2010, Nano letters.

[8]  Nathan S. Lewis,et al.  Si microwire-array solar cells , 2010 .

[9]  Nathan S Lewis,et al.  Enhanced absorption and carrier collection in Si wire arrays for photovoltaic applications. , 2010, Nature materials.

[10]  Nathan S. Lewis,et al.  Energy-Conversion Properties of Vapor-Liquid-Solid–Grown Silicon Wire-Array Photocathodes , 2010, Science.

[11]  Nathan S. Lewis,et al.  Repeated epitaxial growth and transfer of arrays of patterned, vertically aligned, crystalline Si wires from a single Si(111) substrate , 2008 .

[12]  Peidong Yang,et al.  Silicon nanowire radial p-n junction solar cells. , 2008, Journal of the American Chemical Society.

[13]  J. Rand,et al.  Silicon Nanowire Solar Cells , 2007 .

[14]  Kok-Keong Lew,et al.  Silicon nanowire array photelectrochemical cells. , 2007, Journal of the American Chemical Society.

[15]  Nathan S. Lewis,et al.  Growth of vertically aligned Si wire arrays over large areas (>1 cm^2) with Au and Cu catalysts , 2007 .

[16]  Nathan S. Lewis,et al.  Comparison of the device physics principles of planar and radial p-n junction nanorod solar cells , 2005 .

[17]  Peidong Yang,et al.  Low-temperature wafer-scale production of ZnO nanowire arrays. , 2003, Angewandte Chemie.