Open AccessStudy on thermal conductivity of porous silicon thermal isolation layer based on micro-structure mathematical model
Author(s) -
Lujia Xu,
Ming Hu,
Yang Hai-bo,
Yang Meng-Lin,
Jie Zhang
Publication year - 2010
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.59.8794
Subject(s) - thermal conductivity , materials science , porous silicon , porosity , silicon , porous medium , composite material , thermal , conductivity , thermodynamics , optoelectronics , chemistry , physics
Porous silicon can be used as a thermal isolation layer because of its low thermal conductivity. Different from other models based on the mechanism that the thermal conductivity of porous silicon is attributed to complex microcosmic thermal conductivity through such as boundary scattering, the model used in this paper is based on the mechanism that the low conductivity of the porous silicon material is due to its structure factors, such as the existence and distribution of pores and porous silicon is viewed as a compound microstructure piece, which is constructed by both silicon continuous material and pore continuous material medium, connecting in parallel and series patterns. Therefore, the authors give a more understandable and simpler reason why the conductivity of such a material is at such a low level. It is pointed out that the influence of porosity on equivalent thermal conductivity can be divided into two parts: vertical and horizontal, thereby giving semi-quantitative relationships between the porosity and equivalent thermal conductivity for different pore structures and distributions. A comparison between the calculated results and experimental results shows the validity of this model, thus supporting the reason why the thermal conductivity of porous silicon material is relatively low.