The Influence of Argon Pressure on the Structural and Physical Properties of LaB6 Films
Lanthanum hexaboride (LaB6) films were deposited on Si (111) substrates by magnetron sputtering method. The characterization of the films was investigated by means of atom force microscopy (AFM), X-ray diffraction (XRD), four-point probe electrical resistance measurement, scratch tester and nano-indentation tester. Influence of argon pressure on physical properties, such as crystallization degree, conductivity and mechanical properties was studied. All the films were smooth and dense. The film crystallites showed a preferential orientation of (100) plane, but the films which were deposited at 2.0 Pa exhibited amorphous structures. LaB6 films which were deposited below 1.5 Pa had excellent conductivity. The bonding strength of the films which were deposited at 1.0 Pa was higher than the others due to the formation of the nano-sized crystals. The hardness and elastic modulus were investigated in connection with the crystalline of LaB6 films. As a result, the films which were deposited at 1.0 Pa had a maximal value of hardness (16.782 Gpa) and elasticity modulus (193.895 Gpa). In a word, the LaB6 films which were deposited at 1.0 Pa have a higher degree of crystalline and more excellent physical properties in comparison with the others. The obtained results will be used synthesizing LaB6 films for applications in low-temperature thermoelectric devices.
X. H. Zhao et al., "The Influence of Argon Pressure on the Structural and Physical Properties of LaB6 Films", Applied Mechanics and Materials, Vols. 55-57, pp. 1436-1440, 2011