AVS 52nd International Symposium
    Electronic Materials and Processing Thursday Sessions
       Session EM2-ThM

Paper EM2-ThM11
Local Origins of Catalytic and Sensor Activity in 1D Oxide Nanostructures: From Spectromicroscopy to Device

Thursday, November 3, 2005, 11:40 am, Room 310

Session: Heteroepitaxy and Low-Dimensional Structures
Presenter: A. Kolmakov, SIUC
Authors: A. Kolmakov, SIUC
U. Lanke, University of Saskatchewan, Canada
S.V. Kalinin, Oak Ridge National Laboratory
Correspondent: Click to Email
When nanowire radius (or nanobelt's thickness) is comparable with its Debye length, the adsorption/desorption of donor/acceptor molecules on the surface of the nanowire (nanobelts) drastically alters the bulk electron density inside the nanowire manifesting superior performance of nanostructure as a chemical sensor as an example. For the nanostructures which are functionalized with catalytic particles this appears to be an oversimplified picture. The sensing effect of such 1-D metal oxide chemiresistor or chemi-FET can have completely different origins like spillover effect from catalyst particles, gas induced barrier modulations of the local electroactive element (nanoparticles, defects etc)or transient processes in the gate oxide. To explore the relative importance of these phenomena on catalytic and sensing performance of 1D nanostructures, adsorbate specific, microscopic techniques have to be developed. We have tested a range of imaging techniques to address local transport behavior in the working metal oxide nanostructure wired as chemiresitor and chemi-FET. In particular, we have developed the experimental techniques and preparative protocols for implementation of synchrotron radiation based spectro-microscopies (SPEM and X-PEEM) to individual 1D nanostructures. Using X-PEEM in NEXAFS mode we demonstrated the ability to reveal submicron lateral compositional and electronic (work function) inhomogeneouties in individual nanowire. We were also complemented our results with Scanning Impedance Microscopy (SIM) and Scanning Surface Potential Microscopy (SPPM) to acquire ac and dc potential distributions in an operating nanowire device. These results open new avenue to visualize the adsorption /desorption phenomena on the surfaces of the individual nanostructure both in real time and at nano- and mesoscopic level.