Reproductive behaviour

368 ref. chap. 7International audienc

Reproductive behaviour

368 ref. chap. 7International audienc

Study of the effect of gas pressure and catalyst droplets number density on silicon nanowires growth, tapering, and gold coverage

We investigated the growth of silicon nanowires from Au-rich catalyst droplets by two different methods: chemical vapor deposition (CVD) and molecular beam epitaxy (MBE). The growth rate is found to be diameter-dependent and increases with increasing precursor partial pressures. The comparison of the experimental results with models shows that the contribution of Si atoms that diffuses from the substrate and the NW sidewalls toward the catalyst droplet can be neglected in CVD for the different pressures used in this study, whereas it is the major source of Si supply for the MBE growth. In addition, by decreasing the number density of catalyst droplet prior to the NW growth in CVD, it is also found that this parameter affects the NWs morphology, increasing the tapering effect when the silane partial pressure is small enough to allow gold atom diffusion from the catalyst drople

Atomic scale dopant metrology in an individual silicon nanowire by atom probe tomography

International audienceIn this work, the p-type silicon nanowires (SiNWs) are grown by the Chemical Vapor Deposition (CVD) method using gold as catalyst droplet, silane as precursor and diborane as dopant reactant and are analyzed at the atomic scale using the three dimensional laser assisted Atom Probe Tomography (APT). This paper reports the preparation of SiNWs and their observation. A three dimensional dopant distribution and its accurate concentration are determined. The possible dopant incorporation pathway into an individual SiNW is also discussed