CPM Seminar

Solute Trapping on the Nanoscale

Oussama Moutanabbir

Department of Engineering Physics
École Polytechnique de Montréal

Impurity trapping at a moving solid-liquid interface is a well-documented phenomenon observed in a variety of bulk metal-semiconductor systems at extremely high interface velocities reaching a few m/s [1, 2]. Exploring this phenomenon in nanoscale systems has revealed unexpected effects that challenge the current theories. In this presentation, we discuss the inconsistencies in these theories and describe the atomistic-level behavior of impurities in metal-catalyzed silicon nanowires. More specifically, we address the incorporation of the catalyst atoms into a growing nanowire based on three-dimensional atom-by-atom mapping of individual nanowires using highly focused ultraviolet laser-assisted atom-probe tomography. Besides the technological implications, the observed kinetics-driven colossal injection also has direct implications for nanowire growth and morphology. The control of this phenomenon provides myriad opportunities to create entirely new class of nanoscale devices by precisely tailoring shape and composition of metal-catalyzed nanowires.

References:
[1] K. A. Jackson, Can. J. Phys. 36, 683 (1958).
[2] J. C. Baker & J. W. Cahn, Acta Metall. 17, 575-578 (1969).