Fabrication of Flat MgO(111) Films on Al2O3(0001) Substrates by Pulsed Laser Deposition

Abstract

We have found that epitaxial MgO(111) thin films grow under a wide range of deposition conditions (substrate temperatures of 400–800 °C, oxygen partial pressures of 10-4–100 Pa) on α-Al2O3(0001) substrates by pulsed laser deposition (PLD), despite the strongly divergent electrostatic potential of MgO(111). The surfaces of the resulting thin films show step-and-terrace structures reflecting the surface of α-Al2O3(0001) with a small root-mean-square roughness of 0.62 nm even at a film thickness of 80 nm. These results present the possibility of fabricating various artificial oxide structures using flat MgO(111) films produced by a conventional PLD technique.