Plasma plume effects on the conductivity of amorphous-LaAlO₃/SrTiO₃ interfaces grown by pulsed laser deposition in O₂ and Ar

Amorphous-LaAlO3/SrTiO3 interfaces exhibit metallic conductivity similar to those found for the extensively studied crystalline-LaAlO3/SrTiO3 interfaces. Here, we investigate the conductivity of the amorphous-LaAlO3/SrTiO3 interfaces grown in different pressures of O2 and Ar background gases. During the deposition, the LaAlO3 ablation plume is also studied, in situ, by fast photography and space-resolved optical emission spectroscopy. An interesting correlation between interfacial conductivity and kinetic energy of the Al atoms in the plume is observed: to assure conducting interfaces of amorphous-LaAlO3/SrTiO3, the kinetic energy of Al should be higher than 1 eV. Our findings add further insights on mechanisms leading to interfacial conductivity in SrTiO3-based oxide heterostructures.© 2012 American Institute of Physics.