A qualitative approach for determination of thermal conductivity in semiconductor nanocrystals

The author has formulated a qualitative method to determine the effective thermal conductivity variation in nanomaterials with respect to their dimension and size. The model includes the impact of shape, size, dimension and increased phonon scattering in nanomaterial due to the thermal resistance. In the present work, Guisbier�s top-down approach is used to obtain the thermal conductivity expression in terms of size and shape factor. The effective thermal conductivity of the nanomaterial is deduced using the effective medium approach that help to find the thermal conductivity in nanomaterial based on Kapitza thermal resistance effect. The model approach predicts the increment in the thermal conductivity of nanomaterial with size increment. The Kapitza thermal resistance in nanosolids results in increase in Phonon scattering in nanosolids with size reduction to nanoregime. The effective thermal conductivity is determined in AlN, GaN, GaAs, InAs and ZnO semiconducting compounds with respect to size in spherical and tetrahedral nanoparticles; cylindrical and parallelopiped nanowires and nanofilms. The model results obtained are compared with available experimental and simulated data. Good consistency between the compared results is observed in graphical representations. The model shows a drastic drop in effective thermal conductivity in nanosolids with their size reduction that increases the figure of merit in nanomaterials for using them in thermoelectric devices.