Toward Mechanosynthesis of Diamondoid Structures: X. Commercial Capped CNT SPM Tip as Nowadays Available C_2 Dimer Placement Tool for Tip-Based Nanofabrication

摘要

According to Drexler, advanced mechanosynthesis will employ advanced nano-machines, but advanced nano-machines will themselves be products of advanced mechanosynthesis. This circular relationship must be broken via TBN technology development. In this article, the possibility of using easily available commercial CNT tips to assemble carbon-based intermediate generations of nano-devices is considered. Mechanosynthesis of a target class of carbon-based nano-devices will require molecular tools capable of transferring C_2 molecules to reaction sites that have binding energies in the range of -6.9 to -7.4 eV per carbon atom or -7.6 to -8.6 eV per C_2 molecule. Desirable properties of tools include approximately exoergic transfer of moieties to these structures; good geometrical exposure of moieties; and structural, electronic and positional stability. The results presented in this paper suggest that the CNT tips now available on the market have adequate properties to become tools for C_2 molecule transfer, into a reaction site during positional mechanosynthesis. The surpassing features of the commercial single/double wall capped CNT tips such as, small tip radii, extreme aspect ratio, excellent wear-out behavior and the average low temperature binding energy of C_2~-5.0±1.2 eV make them the ideal tools for bridging the gap between present-day tip-based nanofabrication (TBN) and future implementation of advanced nanotechnology.