Pulsed Laser Deposition of High-Quality Manganite Thin Films at Low Background Pressures with in-situ Reflection High Energy Electron Diffraction

摘要

We have developed a methodological approach which allows the deposition of high quality fully oxidized manganite thin films at low oxygen background pressure (10{sup}(-4) - 10{sup}(-3) mbar) by PLD. In such oxygen conditions the thickness of the deposited layer can be controlled at the level of a single unit cell by the use in situ of a conventional Reflection High Energy Electron Diffraction diagnostic. We show that by decreasing the laser fluence it is possible to improve the oxidation process in thin films under low background oxygen pressure. Films deposited at low laser fluence (about 0.2 J/cm{sup}2) show a two-dimensional growth mode and possess very good transport properties without the necessity of any further post-growth annealing treatment. A physical model, based on the plume-background interaction as a primary mechanism of film oxidation during growth, is proposed to explain the experimental findings.