In a consequence of redefined nanoscale plasticity: Nanoscale Diffusion in Nanodeformed Semiconductors

Project Details


The present application is a direct consequence of the fresh Finnish discovery (the research carried out within the national FINNANO-program) made together with the research team of Hysitron Inc. (USA) that results in a major shift in our understanding of the nano-scale deformation of solids. It was recently revealed that plasticity of semiconductors - being viewed so far strictly in terms of dislocations nucleation and motion, reflects instead frequently a phase transition. The latter is marked by a drastic singularity in nano-mechanical response accompanied by intriguing new electrical nano-phenomenon the Current Spike. Such a behavior was predicted by MD simulations of locally stressed GaAs, and recently experimentally verified, indicating a common origin of electrical
and mechanical nanoscale effects the entirely new topic that is fascinating from the scientific point of view and important for the modern technology. Indeed, the first disclosure of the indicated relationship ultimately leads to advances in pressure-sensing, pressure-switching, and future phase-change applications.
Further advances in nanotechnology applications, however, require detailed knowledge of the freshly discovered tiny aspects of the new nano-phenomenon. One issue is already recorded time-dependence of the coupled Current-
Spike/Pop-In (CS-PI) effect that is supposed to be linked to diffusion of donor-atoms in semiconductor, while the other concerns appearance of CS in different structures. Consequently, this project targets nano-scale diffusion of
silicon-donor in strained GaAs. Based on the experimental results diffusion mechanisms are identified by combination of first principles and molecular dynamics calculations. The study aim to clarify some still unexplored phenomena associated with elastic and plastic deformation of GaAs as there are implications that mechanical properties of GaAs with respect to Si concentration depends on the scale on which experiment is performed. Also, it is expected that research provides essential information on application level about Si behavior in strained Si doped GaAs heterostructures.
The Project is initiated by the Finnish-American team (NHL-Hysitron Inc.) that discovered new CS-effect, and joined by the diffusion expert - Prof. Räisänen of Helsinki University. This secures Project admission to the American prototype nanoindentation equipment installed in Minneapolis, USA and advanced Finnish facilities.
Effective start/end date01/01/201031/12/2013


  • Suomen Akatemia: €100,000.00

Fields of Science

  • 114 Physical sciences