• Saunier, Sébastien
• Benaben, Patrick
• Blayac, Sylvain
• Gupta, Anshul

Abstract

In the past decades, introduction of nanostructured materials created a breakthrough allowing the improvement of thermoelectric materials figure of merit. Nanostructuration of silicon through sintering of nanoparticles has been widely reported as an efficient thermoelectric material. Fabrication of flexible thermoelectric devices that could be incorporated in system-in-package as energy generator is a stimulating challenge. In this objective, inkjet printing of silicon nanoparticles was performed on various substrates through jetting parameters optimization and chemical treatments for surface energy tailoring. An annealing step was applied for recovering of electrical conduction and modification of thermal conductivity. Two types of sintering methods under nitrogen were evaluated: Rapid Thermal Annealing and microwave annealing. Morphological evolution was monitored by scanning electron microscopy and Raman microspectroscopy. The latter was also used for evaluation of the thermal conductivity. First steps of sintering have been observed at temperature as low as 600 °C. Thermal conductivity can be tailored from values ~1W/mK up to ~100W/mK by varying the temperature and the length of the annealing step. Electrical conductivity is improved up to 800 °C where oxidation takes place and limits carriers transport. Doping of the nanoparticles will now be performed in order to improve the electrical conductivity and realize a printed thermoelectric device.

Topics

• nanoparticle
• impedance spectroscopy
• surface
• scanning electron microscopy
• Nitrogen
• Silicon
• annealing
• thermal conductivity
• electrical conductivity
• sintering
• surface energy