Fe_(1-x)Co_xSi_2薄膜的光学性质实验研究(英文)

Experimental Study of Optical Properties of Fe_(1-x)Co_xSi_2 Thin Films

用反应沉积法 (RDE)制备了一系列铁钴硅化物即 Fe( 1 - x) Cox Si2 薄膜 ,样品中掺杂的 Co含量由卢瑟福背散射 (RBS)确定。本文研究了样品的光学性质 :室温下在 0 .2 6～ 4.80 e V的光子能量范围内 ,用椭圆偏振光谱仪测量了样品的复介电函数谱。实验发现 ,Fe( 1 - x) Cox Si2 薄膜的介电函数强烈地依赖于薄膜的状态 :a)对于 β相的 Fe( 1 - x ) Cox Si2 样品 ,其介电函数谱在红外低能区呈现出干涉峰 ,对应于半导体态 ;b)对于同时存在 β相和 Σ相的混合相 Fe( 1 - x ) Cox Si2 样品 ,其介电函数谱呈现出半导体和金属的混合态特征 ;c)对于Σ相的 Fe( 1 - x) Cox Si2 样品 ,其介电函数谱呈现出明显的金属态特征。 XRD实验结果表明 ,样品介电函数谱的差异来源于薄膜中不同的 Fe- Si相 ,而与样品中掺

A series of Fe (1-x) Co xSi 2 thin films with variation of x was prepared by reactive deposition epitaxy (RDE) method.The optical properties of the samples are reported in this paper.The dielectric function of the samples was measured by spectroscopic ellipsometer in the photon energy range of 0.26～4.80 eV at room temperature.It's interesting to find that the dielectric function of Fe (1-x) Co xSi 2 films is strongly dependent on the phase of the films:a) The dielectric function spectra show interference peaks in the low photon energy range for the β phase Fe (1-x) Co xSi 2 samples;b) The dielectric function spectra show a feature between the semiconductor and metal feature for the samples containing both β and Σ phase Fe (1-x) Co xSi 2;c) The dielectric function spectra show metal feature for the Σ phase Fe (1-x) Co xSi 2 samples.According to the x ray diffraction(XRD) results,the variation of the dielectric spectra is arisen from the change of the Fe Si phase in the samples,rather than that from the variation of x.