Nonstoichiometric material transfer in the pulsed laser deposition of LaAlO3

Inequivalent angular distributions have been found for La and Al in the ablation plume from LaAlO3 single crystal targets using a KrF laser during pulsed laser deposition. Angular distributions and stoichiometries in the condensate were measured and reveal decidedly nonstoichiometric transfer from target to substrate over most of the angular range. Composition varied dramatically for plume angles parallel to the long axis of the laser spot with the on-axis position exhibiting a peak in the La/Al atom ratio at ∼1.5. The distributions were more diffuse in the perpendicular direction. Stoichiometric LaAlO3 was found in the condensate only at an extreme off-axis position.