Growth of highly oriented γ- and α-Al2O3 thin films by pulsed laser deposition

Abstract Highly oriented aluminum oxide (Al 2 O 3 ) thin films were grown on SrTiO 3 (100), α-Al 2 O 3 (1102), α-Al 2 O 3 (0001) and MgO (100) single crystal substrates at an optimized oxygen partial pressure of 3.5×10 −3  mbar and 700 °C by pulsed laser deposition. The films were characterized by X-ray diffraction and atomic force microscopy. The X-ray diffraction studies indicated the highly oriented growth of γ-Al 2 O 3 (400) ǁ SrTiO 3 (100), α-Al 2 O 3 (024) ǁ α-Al 2 O 3 (1102), α-Al 2 O 3 (006) ǁ α-Al 2 O 3 (0001) and α-Al 2 O 3 (006) ǁ MgO (100). Formation of nanostructures with dense and smooth surface morphology was observed using atomic force microscopy. The root mean square surface roughness of the films were 0.2 nm, 0.5 nm, 0.7 nm and 0.3 nm on SrTiO 3 (100), α-Al 2 O 3 (1102), α-Al 2 O 3 (0001) and MgO (100) substrates, respectively.