Grain-size-dependent thermal conductivity of nanocrystalline yttria-stabilized zirconia films grown by metal-organic chemical vapor deposition

A grain-size-dependent reduction in the room-temperature thermal conductivi ty of nanocrystalline yttria-stabilized zirconia is reported for the first time. Films were grown by metal-organic chemical vapor deposition with cont rolled grain sizes from 10 to 100 nm. For grain sizes smaller than approxim ately 30 nm, a substantial reduction in thermal conductivity was observed, reaching a value of less than one-third the bulk value at the smallest grai n sizes measured. The observed behavior is consistent with expectations bas ed on an estimation of the phonon mean-free path in zirconia. (C) 2000 Amer ican Institute of Physics. [S0003-6951(00)05034-8].