Thermal properties of two types of porous silicon are studied using the pulsed-photothermal method (PPT). This method is based on a pulsed-laser source in the nanosecond regime. A 1D analytical model is coupled with the PPT technique in order to determinate thermal properties of the studied samples (thermal conductivity and volumetric heat capacity). At rst, a bulk single crystal silicon sample and a titanium thin lm deposited on a single crystal silicon substrate are studied in order to validate the PPT method. Porous silicon samples are elaborated with two dierent techniques, the sintering technique for macroporous silicon and electrochemical etching method for mesoporous silicon. Metallic thin lms are deposited on these two substrates by magnetron sputtering. Finally, the thermal properties of macroporous (30% of porosity and pores diameter between 100 nm and 1000 nm) and mesoporous silicon (30% and 15% of porosity and pores diameter between 5 nm and 10 nm) are determined in this work and it is found that thermal conductivity of macroporous (73 W.m-1 .K-1) and mesoporous (between 80 and 50 W.m-1 .K-1) silicon is two times lower than the single crystal silicon (140 W.m-1 .K-1).
International audienceDeposition of gold containing oxygen thin films was carried out at room temperature onto silicon substrates by reactive magnetron sputtering under Ar/O2 plasma. Nuclear reaction analysis of films shows that different oxygen concentrations (AuOx with x = 0 to 1.2) can be reached depending on the growth conditions. X-ray diffraction and scanning electron microscopy of the deposited samples evidence nanocrystallised films formed of pure Au phase or of Au metal mixed to a low ordered Au2O3 phase. The films display a columnar growth with grains in the 20-30 nm size range. A higher resistivity than that of pure gold is systematically measured by a four probe method. The electrical resistivity of the films was found to be correlated to the mean oxygen amount, and also to the microstructure of the Au phase
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