  Anisotropic nanomaterials possess interesting thermal transport properties
because they allow orientation of heat fluxes along preferential directions due
to a high ratio (up to three orders of magnitude) between their in-plane and
cross-plane thermal conductivities. Among different techniques allowing thermal
conductivity evaluation, micro-Raman scattering is known to be one of the most
efficient contactless measurement approaches. In this letter, a new
experimental approach based on Raman scattering measurements with variable
laser spot sizes is reported. Correlation between experimental and calculated
thermal resistances of one-dimensional nanocrystalline solids allows
simultaneous estimation of their in-plane and cross-plane thermal
conductivities. In particular, our measurement approach is illustrated to be
successfully applied for anisotropic thermal conductivity evaluation of silicon
nanowire arrays.
