| AVS 54th International Symposium | |
| In-situ Electron Microscopy Topical Conference | Monday Sessions |
| Session IE-MoA |
| Session: | Dynamics of Nanostructures |
| Presenter: | E.A. Stach, Purdue University |
| Authors: | E.A. Stach, Purdue University B.-J. Kim, Purdue University S.-M. Kim, Purdue University D.M. Zakharov, Purdue University F.M. Ross, IBM T.J. Watson Research Center J. Tersoff, IBM T.J. Watson Research Center S. Kodambaka, UCLA M.C. Reuter, IBM T.J. Watson Research Center K. Reuter, IBM T.J. Watson Research Center B. Maruyama, Wright Patterson Air Force Research Laboratory M. Pender, Wright Patterson Air Force Research Laboratory |
| Correspondent: | Click to Email |
Semiconducting nanowires and carbon nanotubes are two of the primary 'new' materials of interest in the field of nanotechnology, This is because their small dimensions and unusual structures allow for new technologies to be established that exploit their unique electronic properties. We have been focused on understanding the mechanisms and kinetics associated with their nucleation and growth, in an attempt to provide a scientific framework for controlling their structure. Through the use of in-situ chemical vapor deposition in both ultra-high vacuum and at elevated pressures, we can observe the mechanisms of nucleation and quantitatively characterize the kinetics of these processes. In the case of vapor-liquid-solid silicon nanowire growth, we have found that the dissociative desorption of disilane is the rate limiting step. Additionally, after nucleation, we find that the nuclei undergo a rapid growth in size, driven by the supersaturation of silicon in the host gold-silicon liquid alloy drop. We will present a theoretical framework to describe this behavior which balances the roles of supersaturation, pressure and interface energies and show how this can be used to find the kinetic liquidus line in the AuSi phase diagram. In the case of carbon nanotube growth, we utilize a unique catalyst approach wherein the catalysts are firmly embedded in a silicon dioxide support film, so as to permit high resolution images of their surface structure at the onset of nanotube growth via the alcohol catalytic chemical vapor deposition process. We will report quantitiative measurements of catalyst coarsening, and discuss how this process plays a controlling role in nanotube nucleation and subequent growth. In each case, we will emphasize the power of the in-situ approach for providing quantiative data for discovering unique information regarding fundamental growth processes.