Growth, interfacial microstructure and optical properties of NiO thin films with various types of texture

Abstract

International audienceNiO thin films with random, fiber and in-plane textures have been successfully deposited at near room temperature by reactive magnetron sputtering on glass, silicon and Al 2 O 3 (0001) substrates. Self-texture related with the deposition conditions and crystallographic characters competes with the driving force from the matched substrate. Such a competition can be used to control the texture of thin films on matched substrates, especially when the promoting orientations from self-texture and substrate are different. Enhancing this competition tends to suppress the self-texture of NiO thin films on Al 2 O 3 (0001) substrates, whereas restricting the competition is beneficial to produce the in-plane textured NiO thin films. In addition, it is found that the optical transmittance of NiO thin films on Al 2 O 3 (0001) substrates can also be tuned by such competition. Interfacial microstructure analyses of NiO thin films on amorphous substrates clearly evidence the existence a nanocomposite layer at the initial growth, which is composed of NiO nanocrystals surrounded by amorphous matrix. In contrast, in-plane textured NiO thin films on Al 2 O 3 (0001) substrates exhibit sharp interface without nanocrystals or amorphous matrix. We believe these results provide a general framework of tuning the textures and properties of thin films on matched substrates