Tuning The Crystallographic Structure And Morphology Of Nanocrystalline CaB6 Films Deposited By DC Magnetron Sputtering

Abstract

Through changing the argon pressure, CaB6 films with different crystallographic orientation and morphology on glass substrates were prepared by direct current (DC) magnetron sputtering method. The film textures, crystallite sizes, composition and morphology were investigated by a spectrum of characterizing techniques in terms of X-ray diffraction (XRD), field emission scanning electron microscopy with energy dispersive spectrometer (FESEM-EDS), atomic force microscopy (AFM), Raman shift spectroscopy. The influence of argon pressure on microstructure was studied. The average grain size increased with the argon pressure increasing from 0.8 Pa to 1.5 Pa. Meanwhile, the dominant crystal face changed from (110) to (100). Then the grain size decreased when the argon pressure increased to 2.0 Pa. The surface morphology evolved from typical cauliflower-like nanocrystalline clusters to faceted rectangular pyramids. It was found that considerable amount of argon atoms were trapped in the films. The formation process of CaB6 films was also analyzed in this paper.

Keywords

• CaB6 films
• crystallographic structure
• morphology
• argon pressure