Growth of Rare Earth Silicide Epitaxial Nanowires on Si(001)

J. Nogami

Department of Chemical Engineering and Materials Science,

Michigan State University, East Lansing, MI 48824 USA

Several groups have recently reported growing nanowires of rare earth (RE) metal silicides on the Si(001) surface [1-3]. These nanowires grow by self assembly during the deposition of the RE metal on the Si(001) surface. They have many desirable properties such as crystalline structure, metallic conduction, and micron scale length. STM and STS results on Dy, Ho, and Gd silicide nanowires will be shown. Metal coverage, growth temperature, substrate step density, and post growth annealing duration all have strong effects on nanowire morphology. The differences in growth behavior between these metals will be discussed, particularly with regard to the optimization of nanowire growth.

STM images (300 nm x 300 nm) showing (a) a nanowire covered surface formed by depositing 0.63 monolayers (ML) Gd on a flat Si(001) substrate, and (b) a parallel nanowire covered surface free of islands formed by depositing 0.77 ML Gd on a vicinal Si(001) substrate. The inset in (a) magnifies the area in the white box, showing individual nanowires within a bundle. [1]C. Preinesberger, S. Vandré, T. Kalka, and M. Dähne-Prietch, J. Phys. D: Appl. Phys. 31, L43 (1998). [2]Y. Chen, D. A. A. Ohlberg, G. Medeiros-Ribeiro, Y. A. Chang, and R. S. Williams, Applied Physics Letters 76, 4004 (2000). [3]J. Nogami, B. Z. Liu, M. V. Katkov, C. Ohbuchi, and N. O. Birge, Phys. Rev. B 63, 233305 (2001).