title: Effect of high magnetic field on structure and oxygen adsorption of CuO films.
abstract: CuO films have been fabricated by a two-step method: depositing Cu films on single crystal Si substrates by magnetron sputtering; thermal oxidation of the as-deposited Cu films in the air at 600 degrees C. To investigate the effect of magnetic field on CuO film growth, a series of static fields are added along the substrate in the oxidation process. Field emission scanning electron microscopy shows that the high magnetic field promotes the densification and the grain refinement of the films. The X-ray diffraction results reveal that the films have monoclinic structure of CuO. The relative intensity of (111) peak strengthens gradually with increasing the magnetic field intensity, implying that the magnetic field facilitates the growth along [111] direction. X-ray photoelectron spectra of Cu 2p core-level indicate that +2 is the main valence state for Cu ions in CuO films, and the magnetic field produces deeper oxidation of the samples. The high binding energy part of O 1s XPS spectra, which reflects the oxygen adsorption ability, shrinks at low magnetic field, and then expands with the further increase of the magnetic field. The mediation of oxygen adsorption is related to the improvement of crystallinity as well as the enlarged boundary areas. The present study opens a new way to fabricate CuO films, and the high magnetic field is an effective way to tuning the oxygen adsorption.
authors: Department of Material Science and Engineering, Tsinghua University, Beijing 100084, China.
authors: H
authors: H
authors: Jiang
authors: X F
authors: XF
authors: Liu
authors: Z Y
authors: ZY
authors: Zou
authors: R H
authors: RH
authors: Tang
authors: W
authors: W
authors: Liu
authors: R H
authors: RH
authors: Yu