Éditeur(s) : HAL CCSD ACS American Chemical Society - Publications
Résumé : International audience
ABSTRACT: In this paper, the structural, optical and thermal properties of n-type (100),p-type (100) and (111) mesoporous silicon (MePSi) are reported. The mesoporous silicon wasprepared by an electrochemical process from bulk silicon wafer. Depending on the etchingdepth, analyses show that the porosity of p-type (111) increased by 32 to 40% compared to p(100) which, in turn, increased by 22 to 48% compared to n-type (100). The structuremorphology and the abundance of Si-Ox and Si-Hy also depended heavily on the type andcrystal orientation of MePSi. The thermal properties of the MePSi layers such as thermalconductivity (κ), volumetric heat capacity (ρCp) and thermal contact resistance (Rth) weredetermined using the pulsed photothermal method. The thermal conductivity of bulk silicondropped sharply after etching, decreasing by more than twenty-fold in the case of n-type (100)and by over forty-five fold for p-type (100) and (111). According to the percolation modeldepending on both porosity and phonon confinement, the drop in thermal conductivity wasmainly due to the nanostructure formation after etching. Thermal investigations showed thatthe volumetric heat capacity (ρCp) followed the barycentric model which depends mainly onthe porosity. The thermal contact resistances of MePSi layers were estimated to be in therange of 1x10-8 to 1x10-7 K⋅m2⋅W-1.
The Journal of Physical Chemistry C

hal-01495490
https://hal.archives-ouvertes.fr/hal-01495490
DOI : 10.1021/acs.jpcc.6b13101