title: Thermal transport in nanoporous silicon: interplay between disorder at mesoscopic and atomic scales.
abstract: We present molecular and lattice dynamics calculations of the thermal conductivity of nanoporous silicon, and we show that it may attain values 10-20 times smaller than in bulk Si for porosities and surface-to-volume ratios similar to those obtained in recently fabricated nanomeshes. Further reduction of almost an order of magnitude is obtained in thin films with thickness of 20 nm, in agreement with experiment. We show that the presence of pores has two main effects on heat carriers: appearance of non-propagating, diffusive modes and reduction of the group velocity of propagating modes. The former effect is enhanced by the presence of disorder at the pore surfaces, while the latter is enhanced by decreasing film thickness.
authors.affiliation: Department of Chemistry, University of California, Davis, California 95616, United States.
authors.forename: Yuping
authors.initials: Y
authors.lastname: He
authors.forename: Davide
authors.initials: D
authors.lastname: Donadio
authors.forename: Joo-Hyoung
authors.initials: JH
authors.lastname: Lee
authors.forename: Jeffrey C
authors.initials: JC
authors.lastname: Grossman
authors.forename: Giulia
authors.initials: G
authors.lastname: Galli
mesh_terms: D003198:Computer Simulation; D004735:Energy Transfer; D006358:Hot Temperature; D046911:Macromolecular Substances / Q000737:chemistry; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D016062:Porosity; D012825:Silicon / Q000737:chemistry*; D013499:Surface Properties; D013814:Thermal Conductivity
chemical_list: D046911:Macromolecular Substances; D012825:Silicon