Manipulation of ion energies in pulsed laser deposition to improve film growth
Xiang Yao, Christof W. Schneider, Thomas Lippert, and Alexander Wokaun
The growth and crystallinity of oxide thin films using a physical vapour deposition technique like molecular beam epitaxy (MBE) or pulsed laser deposition (PLD) is influenced by the flux of materials, the kinetic energy of species, and the substrate temperature. PLD is generating on a short time scale (μs) a large flux of materials, species with large kinetic energies (few eV up to several 10 eV), and requires often higher growth temperatures as compared to oxide MBE. Here, we show as a proof of principle that epitaxial TiO2 thin films can be grown on LaAlO3 (001) at a much-reduced deposition temperature of 300 °C by applying a bias voltage with respect to a grounded substrate. The controlled manipulation of ion energies with an applied electric field can allow to bridge the gap in growth conditions between PLD and oxide MBE.