International audienceNanostructured silicon-based materials are good candidates for thermoelectric (TE) devices due to their low thermal conductivity, customizable electrical conductivity, and reduced cost. Generally, nanostructured TE bulk materials are obtained through compaction and sintering at high temperature (>1000 °C) of silicon nanoparticles (NPs). In order to introduce TE generators in flexible electronic devices, development of thin film TE is needed. Inkjet-printing of silicon NPs-based ink is an interesting technology for this targeted application due to its low cost and additive process. This paper presents the implementation of inkjet-printing of a silicon NPs-based ink toward the fabrication of TE material on flexible substrate and the development of a characterization method for this material. After printing, recovering of electrical properties through sintering is mandatory. Nevertheless, special care must be taken in order to keep thermal conductivity low and reduce the annealing temperature to allow the use of flexible substrates. The functional properties: electrical and thermal (measured by Raman spectroscopy), are studied as a function of the annealing process. Two types of annealing: rapid thermal annealing and microwave annealing, are investigated as well as two atmospheres: inert (N2) and reducing (N2-H2 5%)

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Using tailored voltage waveforms (TVWs) to excite a low pressure, low-temperature plasma discharge, we compare the behavior of three gas mixtures, namely Ar, O 2 and SF 6 /O 2 mixtures, the last of which is currently used for the plasma-texturing of silicon wafers for photovoltaics. The primary goal of using TVWs is to control the ion bombardment energy at the surface of the wafer, and this control is demonstrated through retarding field energy analyzer (RFEA) measurements. However, the complicated electrical response of the plasma to such waveforms makes the ab initio prediction of the ion energy difficult, although by using said RFEA measurements, we show that it can be done approximately by using measured electrical data. In addition, we utilize the response of the plasma to mirror-image 'sawtooth' waveforms as a predictor of the dominant electron heating mode (α or drift-ambipolar, DA). At equivalent pressures and coupled powers, the Ar and O 2 mixtures always display behavior associated with electropositive plasmas (a solely α heating mode). However, with the addition of SF 6 to an O 2 gas flow, a transition can be observed towards a behavior associated with a more electronegative plasma (i.e. a dominant DA heating mode). This crossover in the dominant heating mode is observed through the relative self-bias voltage for each type of sawtooth waveform, and is therefore a useful predictor of the dominant electron heating mode in low pressure, cold plasma discharges.

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