Center for Energy Harvesting Materials and Systems (CEHMS). Bio-Inspired Materials and Devices Laboratory (BMDL)Oak Ridge National Laboratory. Materials Science and Technology DivisionZhao, YuYan, YongkeKumar, AshokWang, HsinPorter, Wallace D.Priya, Shashank2015-05-042015-05-042012-08-010021-8979http://hdl.handle.net/10919/51989In this study, we describe the changes in thermal conductivity behavior of ZnO-Al micro- and nano-two-phase self-assembled composites with varying grain sizes. The reduction in thermal conductivity values of micro-composites was limited to similar to 15% for ZnO-4% Al. However, nano-composites exhibited large reduction, by a factor of about three, due to uniform distribution of nano-precipitates (ZnAl2O4) and large grain boundary area. Interestingly, the micro-composites revealed continuous decrease in thermal conductivity with increase in Al substitution while the nano-composites exhibited the lowest magnitudes for 2% Al concentration. Raman spectra indicated that phonon confinement in ZnO-Al nano-composites causes drastic decrease in the value of thermal conductivity. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4745034]application/pdfen-USIn CopyrightII-VI semiconductorsPhononsThermal conductivityNanocompositesNanopowdersArticle - Refereedhttp://scitation.aip.org/content/aip/journal/jap/112/3/10.1063/1.4745034https://doi.org/10.1063/1.4745034