Thermal conductivity measurement of porous silicon by the pulsed-photothermal method

Abstract

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).

Ultraviolet laser patterning of porous silicon

“…28 Therefore, the C p values reported for c-Si as a function of temperature have been used. To solve Eq.…”

Preparation and Thermal Characterization of Annealed Gold Coated Porous Silicon

“…Hence, a large amount of research work has focused on realizing porous silicon (PSi) based optoelectronic devices, such as light emitting diodes (LED) [8], waveguides [9], optical filters [8], thermal isolators [10], photovoltaic diodes [11], and different types of sensors [12]. The Au/PSi structure can be used as a hydrogen fuel cell or for other applications that require tuneable and lower thermal diffusivity than silicon.…”

Dynamical Study of Heat Transport Properties of Porous Silicon

“…Since the porosity of the etched layer reached up to 70 % (see Fig. 1), the equation 4 (κ c-Si = 140 W•m −1 •K −1 was taken from [7]). Table 1 presents a comparison of the values of thermal conductivity for n-type porous silicon obtained by different authors and by different methods.…”

“…Strong diameter dependence of thermal conductivity in the nanowires was ascribed to the increased phonon-boundary scattering and possible phonon spectrum modification. Experimental studies using the pulsed-photothermal method revealed that the thermal conductivity of macroporous and mesoporous silicon is two times lower than that of the single crystal silicon (140 W•m −1 •K −1 ) [7]. Thermal conductivities of sintered porous silicon films measured at room temperature using a non-contact method based on lock-in thermography ranged from 21 to 2.3 W•m −1 •K −1 ) and decreased with increasing porosity [8].…”