silicon
Fracture strength of micro- and nano-scale silicon components
Silicon devices are ubiquitous in many micro- and nano-scale technological applications, most notably microelectronics and microelectromechanical systems (MEMS). Despite their widespread usage, however, issues related to uncertain mechanical reliability remain a major factor inhibiting the further advancement of device commercialization. In particular, reliability issues related to the fracture of MEMS components have become increasingly important given continued reductions in critical feature sizes coupled with recent escalations in both MEMS device actuation forces and harsh u
Post doctoral position available--nanophotonics
At the nanobiophysics laboratory we are looking for a post doc to participate on an experimental work regarding the tuning of fluorescence in nanoparticles under the effect of pressure. We believe that it is the strain rather the pressure that is causing the shift in the emission. We are also investigating this effect using numerical models. While we are looking for an experimentalist urgently we will be looking for a theoretician/numerical guy in a year. All welcome if you have the right attitude and motivation.
Surface Stress Effects on the Resonant Properties of Silicon Nanowires
Abstract of paper recently accepted for publication in Journal of Applied Physics:
Dynamics of terraces on a silicon surface due to the combined action of strain and electric current
A (001) surface of silicon consists of terraces of two variants, which have an identical atomic structure, except for a 90° rotation. We formulate a model to evolve the terraces under the combined action of electric current and applied strain. The electric current motivates adatoms to diffuse by a wind force, while the applied strain motivates adatoms to diffuse by changing the concentration of adatoms in equilibrium with each step. To promote one variant of terraces over the other, the wind force acts on the anisotropy in diffusivity, and the applied strain acts on the anisotropy in surface stress. Our model reproduces experimental observations of stationary states, in which the relative width of the two variants becomes independent of time. Our model also predicts a new instability, in which a small change in experimental variables (e.g., the applied strain and the electric current) may cause a large change in the relative width of the two variants.