| AVS 60th International Symposium and Exhibition | |
| Scanning Probe Microscopy Focus Topic | Friday Sessions |
| Session SP+AS+EM+GR+MI+NS+SS-FrM |
| Session: | Probing Electronic and Transport Properties |
| Presenter: | P.K. Ng, University of Illinois at Chicago |
| Authors: | P.K. Ng, University of Illinois at Chicago B. Fisher, Argonne National Laboratory N.P. Guisinger, Argonne National Laboratory C.M. Lilley, University of Illinois at Chicago |
| Correspondent: | Click to Email |
The surface of a self-assembled copper-silicide (Cu-Si) nanoisland on a silicon (Si) substrate with (110) orientation was studied using surface tunneling microscopy (STM). Self-assembled Cu-Si nanostructures on Si are of technological interested because of their potential use in nanoscale devices. Self-assembled Cu-Si nanoislands were fabricated by electron beam evaporation of Cu onto a 600°C annealing Si substrate in ultrahigh vacuum (UHV) environment. In prior work, we used transmission electron microscopy (TEM) to analyze material composition of Cu-Si nanostructures via x-ray energy dispersive spectroscopy (XEDS) [1]. The XEDS data of a Cu-Si nanowire show a Cu3Si phase [2]. The size of these nanostructures was on the scale of hundreds of nanometers and high resolution analysis was focused on the cross-sectional (or bulk) material. However, the surface of these self-assembled Cu-Si nanoislands has not yet been studied. Figure 1(a) in the attached supplemental document (and all the referring figures therein) shows a scanning tunneling microscopy (STM) micrograph of a self assembled Cu-Si nanoisland on Si(110). The facets on the nanoisland indicates a single crystal. As seen in Figs. 1(b)-(c), a higher resolution scan and analysis on the same nanoisland indicates a surface periodicity between scan points A to B of ~6.8 Å. These results corroborate that the faceted nanoisland is a single crystal. The surface of the nanoisland appears to have unknown absorbates, possibly from water or hydrogen contaminations, see Fig. 1(b). Interestingly, some of these absorbates do not randomly form on the surface but also in a periodical manner. As such, the surface may have a periodical affinity for certain absorbates. A full discussion of this study will be presented in the AVS proceeding.
[1] P. K. Ng, B. Fisher, K. B. Low, A. Joshi-Imre, M. Bode, and C. M. Lilley, "Comparison between bulk and nanoscale copper-silicide: Experimental studies on the crystallography, chemical, and oxidation of copper-silicide nanowires on Si(001)," Journal of Applied Physics, vol. 111, pp. 104301-7, 2012.
[2] P. K. Ng, B. Fisher, K. B. Low, R. E. Cook, and C. M. Lilley, "Crystallographic studies of self assembled Cu-Si nanowires on Si(001), Si(110), and Si(111)," in preparation, 2013.