采用射频磁控溅射和组合靶在260℃的(111)Si上制备了不同Ni、La含量比的La-Ni-O薄膜.通过拟合2～12.5μm波长范围的反射和透射光谱,得出了薄膜在此区间的折射率和消光系数.薄膜的折射率随波长的增长均呈现单调增大的变化趋势,并且随组分的变化,此趋势没有大的变化.而消光系数的色散却对薄膜的组分具有很大的依赖性.实验结果同时表明,在La含量较高时,薄膜为无定型结构,并且具有较大的电阻率.当Ni、La含量比大于l:1.44后,薄膜具有(100)择优取向的赝立方钙钛矿结构，同时具有金属导电性.薄膜的晶面间距、电导率、折射率和消光系数随着Ni含量的增加具有相似的变化规律.并在Ni:La=1:1时,晶面间距和电阻率达到最小值,对所有实验现象,文中从LaNiO₃薄膜的导电机理出发给出了理论分析,并取得了比较一致的结果.

La Ni O thin films of different La and Ni concentration ratios were deposited on (111)Si at substrate temperature 260℃ by a rf magnetron sputtering system with a combined target. The optical refractive index and extinction coefficient were derived by simultaneously fitting the transmittance and reflectance spectra in the wavelength region of 2～ 12.5 μm.And they increase monotonically with the wavelength, and change significantly with different composition. Results also show that the film is of amorphous structure when La content is too high. The film is with (100) preferred orientation and metallic electric conduction as the atomic concentration ratio of La to Ni is less than 1.44∶1. When the composition gets the stoichiometric composition(Ni∶La=1∶1), the lattice constant and sheet resistivity of the film reach their minimums. A practicable explanation for all experimental results is also developed according to the conducting mechanism of LaNiO₃.