When silicon wafers are produced industrially, a large amount of waste (that we call silicon dust) is produced when the large silicon single crystals are sliced into thin wafers. Silicon dust may have some functionality, because it was originally part of the ingot (single crystal) generated by the Czochralski method and had the potential to become part of a silicon wafer. Silicon dust is now being disposed, in spite of its potential functionality. We are analyzing how carbon dioxide can adsorb and react at the surface of such materials. The figure below depicts the transition state of the adsorption reaction of carbon dioxide over a cluster of silicon atoms (which is…

We are conducting research for elucidating how the surface of silicon crystals grow inside CVD (Chemical Vapor Deposition) reactors. This process is already exploited in industry but the surface growth mechanism is not known. A high-temperature mixture of trichlorosilane (SiHCl3) and hydrogen (H2) is used as the gaseous source gas, and SiCl2 molecules form as reactions occur in the reactor. SiCl2 adsorption is believed to be one of the most important chemical events in the epitaxial growth mechanism of a Si(100) surface. In order to elucidate the chemical reaction mechanism leading to the surface epitaxial growth, other subsequent reactions that should occur (elimination of chlorine atoms from the surface, adsorption…

In collaboration with a colleague in the Department of Biomaterials of the Graduate School of Medicine, Dentistry and Pharmaceutical Sciences of Okayama University, who found that phospholipids (molecules that are the building blocks of cell membranes) can mineralize or, in other words, promote the growth of bone-like materials, our lab is working on the elucidation of the chemical reaction mechanism of the mineralization process of phospholipids. By elucidating such a mechanism, our research may allow the synthesis of molecules that lead to a faster formation of bone-like materials. Phospholipids are bio-organic molecules that contain a phosphate group in the center, a hydrophilic functional group, and a hydrophobic carbon chain. The…