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Thin films of boron carbide (B 12+x C 3-x ) were prepared on glass substrates by a pulsed ion-beam evaporation method. A pulsed proton beam with an energy of 1 MV (peak) and a current of 60 kA was focused on sintered B 12+x C 3-x targets. Ablation plasma was formed from the irradiated targets and thin films were prepared on Pyrex and SiO 2 glass substrates at room temperature. From results of X-ray diffraction, the thin films consisted of a B 12+x C 3-x phase. Using a known relationship between the composition and the lattice parameters, the composition of B 12+x C 3-x thin films was estimated to be x = 0.3 and 1.0, which were close to the nominal composition of the targets. These results indicate that B 12+x C 3-x with different carbon contents has been successfully prepared by IBE without substrate heating or sample annealing. Thermoelectric properties of the thin films were measured. A B 12+x C 3-x thin film with estimated composition of x =0.9 exhibited the highest power factor at room temperature among the B 12+x C 3-x samples reported.

Recent studies have analyzed the viability of generating electricity by means of thermoelectric modules applied to processes with large amounts of waste heat. The simulation of the performance of large-scale designs of thermoelectric generators (TEGs), however, is a very complex task since it involves a coupling between both electrical and thermal phenomena. In addition, a single TEG module contains tenths of small P-type and N-type semiconductor legs, which implies that the simulation must take into account domains with characteristic lengths that vary several orders of magnitude. Here, we propose a methodology for determining the effective heat conductance of a single TEG module that can be employed for simulating the entire element without entry into the details of its inner composition. The effective thermal conductance here proposed can be understood as the coefficient that predicts, at different operating conditions, an upper bound of the electrical power generated by the TEG module.

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