Marc Hornbostel

Production of low-cost solar-grade silicon by reduction of SiF 4 gas with sodium: Technical and industrial developmental status

To meet increasing demand for electrical power using solar photovoltaics, millions of tons of solar-grade silicon costing <

A New Activated Carbon for CO2 Capture from Coal-Fired Boiler Flue Gas

20/kg will be needed. Low-cost solar-grade silicon can be mass produced by burning Na metal in an atmosphere of pure SiF4 gas—an exothermic, fast, and complete reaction. SRI International routinely uses reactors that can produce at rates >20 metric tons per year (mty), and has licensed the technology to several companies. The Si product is completely separated from the by-product NaF by leaching or melt separation. With the direct use of industrially available Na, B and P levels in the Si product are <1 ppm. Using purified Na results in Si with dopant levels as low as 20 ppb. Experimental ingots grown have resistivity of 1 to 30 Ω·cm, with >100 Ω·cm when purified reactants were used. The purity, electronic parameters, and solar cell efficiency of 15% indicate that this silicon is of solar grade and can be a key contributor in developing solar power markets.

Progress on crystalline silicon thin film solar cells by FBR-CVD: Effect of substrates and reactor design

With the current environmental interest in controlling greenhouse gases, there is a new focus on materials that can discriminate between gas molecules by capturing those gases that must be curtailed and releasing those that pose no adverse effects to the atmosphere. Although zeolites can be applied to such tasks, molecular sieve (MS) carbons have an additional advantage in their ability to both adsorb and desorb molecules cyclically with comparatively little energy demand. ATMIs BrightBlack™ MS carbons have been extensively characterized using a variety of techniques and modified for the task of selectively adsorbing CO2 from a synthetic flue gas in a laboratory and a pilot plant falling-bed adsorber system. The integrated falling-bed adsorber system was then moved to a field test location to capture CO2 from flue gas from a coal-fired stoker boiler. In a 7000-cycle test, the carbon captured CO2 at 90% efficiency, generating product CO2 gas with purity greater than 95%.

Steam-Stripping for Regeneration of Supported Amine-Based CO2 Adsorbents

Thin film polycrystalline solar cells on low cost substrates offer an attractive path to large scale production of solar cells with the potential to generate electricity at 1

Characteristics of an advanced carbon sorbent for CO2 capture

/W. SRI International has a propriety technology to deposit Si films in a reactor based on fluidized bed technology. The results presented in this paper show that, with a proper reactor design, Si films can be grown at rates of 7 μm/min and higher. Films are crystalline, with crystallite sizes higher than 20 μm. We have also evaluated the performance of SiO2 diffusion barriers as a potential way towards the use of low cost substrates, such as metallurgical grade Si. Whereas SiO2 layers of 0.1 μm are not sufficient to stop P diffusion from the substrate to the film, 0.7 μm layers are thick enough to accomplish this goal. The reactor configuration can be used for continuous and integrated cell/panel fabrication. At present we are building a first continuous reactor, and in this paper we present some preliminary considerations.