Nanostructures for Energy Optimization – NOE

To investigate low power generator using recycled energy, a software chain will be implemented from atoms to circuits. Atomistic semi empirical approach will be used to capture energy dispersions and scattering mechanisms. Two kinds of transport formalisms - Boltzmann and Green - will be used to simulated nanowire and graphene nanostructures, respectively.

On the one hand, the thermoelectric performance of Si/SiGe nanowires will be evaluated and design guidelines will be proposed. On the other hand, a more fundamental prospect of energy conversion using graphene nanostructures will be investigated.

The Noé project, which intends to provide guidelines to nano-energy converter, will open many commercial applications (providing e.g. alternatives to the micro-batteries of embedded systems that work in biological environment) and will contribute to the sustainable use of electrical energy.

All the codes developed in the project will be available under an open source license.

To improve the sustainability of our electricity consumption, efficient thermal management and energy harvesting are becoming critical issues. In this context, semiconductor nanostructures are expected to improve substantially the energy efficiency in electron devices. For instance thermoelectric nanogenerators able to recycle the huge amount of energy wasted by heat engines or electronic circuits are particularly promising. The use of liquid flux energy to supply embedded systems (a kind of electromechanical conversion) should also emerge as a very effective energy conversion mechanism, typically in a biological environment.
The optimization of power efficiency in such energy converters based on nanostructures requires a good understanding of electronic and thermal transport at the nanoscale. Unfortunately, the standard macroscopic models, i.e. the Fourier heat diffusion equation and drift diffusion equations, do not provide an accurate response to the thermal problem in nanodevices which are smaller than the charge and thermal carrier mean free path. Including the influence of both out-of-equilibrium and quantum phenomena requires the development of advanced models. To fully achieve the efficiency optimization, all aspects must be considered, from the material issue to the device architecture and its final performance in a realistic environment at the circuit level.
The scientific aim of the Noé project is to investigate, at a fundamental level, the physics of coupled electrons and phonons transport in nanostructures, and to propose novel structures providing efficient energy conversion. On the one hand, the thermoelectric performance of Si/SiGe nanowires will be evaluated and design guidelines will be proposed. On the other hand, a more fundamental prospect of energy conversion using graphene nanostructures will be investigated. The thermoelectric conversion and also the more unique electromechanical conversion will be explored.
To investigate low power generator using recycled energy, a software chain will be implemented from atoms to circuits. Atomistic semi empirical approach will be used to capture energy dispersions and scattering mechanisms. Two kinds of transport formalisms - Boltzmann and Green - will be used to simulated nanowire and graphene nanostructures, respectively. On the one hand a fully coupled electron-phonon Monte Carlo simulator will be built. On the other hand a device simulator based on atomistic NEGF formalism including relevant scattering mechanism will be developed. Finally, these advanced device simulators self-consistently coupled with Poisson's equation will be used to calibrate semi-analytical circuit models to assess the actual performance of the tested nanostructures.
The success of the Noé project, which intends to provide guidelines to nano-energy converter, will open many commercial applications (providing e.g. alternatives to the micro-batteries of embedded systems that work in biological environment) and will contribute to the sustainable use of electrical energy. Moreover, since they are useful for the nanotechnology community, all the codes developed in the project will be diffused under an open source license. Additionally, since this Noé software platform will certainly require a lot of computational resources in its research release, a "light" release will be developed to be used in Master’s level classes and within the "nano-société" program from the LAbex NanoSaclay in order to familiarize a large audience to some nanotechnology issues.