0722653_McGrath

1. MRI: Manufacturing of Nanocrystaline Silicon Materials at the University of Rochester James McGrath, University of Rochester, DMR 0722653 The University of Rochester has developed a 15 nm thick, silicon-based nanoporous membrane material: porous nanocrystalline silicon (pnc-Si). Pores in the membrane form spontaneously as an amorphous silicon layer reorganizes into nanocrystalizes at temperatures above 750C. Porosities as high as 10% can be created and pore sizes can be adjusted between 2nm and 80nm by controlling the layer deposition conditions and the temperature profile during rapid heating and cooling. This funding is supporting the purchase of modern instruments for deposition and rapid thermal annealing that are expected to unprecedented control over membrane morphology. The same instrumentation will be used in the construction of solid-state layers using non-porous nanocrystalline silicon multi-layers. The silicon nanomembranes have tremendous commercial potential as molecular filters because their thinness minimizes transport time and because the pore distributions have sharp cut-offs that provide for precise molecular discrimination. The silicon platform also allows the pnci-Si filters to be easily configured into formats that are convenient to particular applications. The image on the right shows the incorporation of a pnc-Si chip in a plastic housing that fits in standard laboratory centrifuge tubes.