Effect of growth induced (non)stoichiometry on the thermal conductivity, permittivity, and dielectric loss of LaAlO3 films

The effect of growth-induced non-stoichiometry on the thermal and dielectric properties of pulsed-laser deposited LaAlO3 thin films is explored. The composition of the LaAlO3 films was characterized via X-ray photoelectron spectroscopy and Rutherford backscattering spectrometry and it is revealed that small deviations in laser fluence result in deviations of cation stoichiometry as large as a few atomic percent. The thermal conductivity is also found to be especially sensitive to non-stoichiometry, with 3%-5% La-excess and La-deficiency resulting in 60%-80% reduction in thermal conductivity. The dielectric constant decreases and the loss tangent increases with increasing non-stoichiometry with differences between La-excess and La-deficiency.