Abstract

Owing to excellent mechanical and wear properties, MoS₂/Al₂O₃ composite thin films have been studied extensively in the recent past. In this work, thin films of MoS₂ and MoS₂/Al₂O₃ composites were deposited on silicon substrates using reactive DC magnetron co-sputtering. The chemical composition in terms of at% and wt% of the composite thin films was confirmed using energy dispersive X-ray spectroscopy. It was evident that the elements were exactly in the same stoichiometric contents as required by their respective empirical formulae. The structural morphology of the grains was visualized using a field emission scanning electron microscopy. The images showed that MoS₂ thin film consisted of large sized grains with a number of spaces, but MoS₂/Al₂O₃ composite showed a very smooth surface without any cracks or free spaces. Furthermore, spectroscopic ellipsometry study was conducted by making a fitting model and comparing the calculated values with it. Refractive index n, extinction coefficient k, thickness t and absorption coefficient α were calculated. From absorption and depolarization of light, it was deduced that MoS₂/Al₂O₃ composite was a very good absorber of high energy rays and a very good reflector of low energy rays in IR region. Optical energy band gap of MoS₂ came out to be 2.68 eV and while that of MoS₂/Al₂O₃ composite remained 2.19 eV.

中文翻译：

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溅射MoS 2和MoS 2 / Al 2 O 3复合薄膜的光学常数比较

摘要

由于优异的机械和磨损性能，最近对MoS ₂ / Al ₂ O ₃复合薄膜进行了广泛的研究。在这项工作中，MoS ₂和MoS ₂ / Al ₂ O _3的薄膜使用反应性直流磁控管共溅射将复合材料沉积在硅基板上。使用能量色散X射线光谱法确认了以复合薄膜的at％和wt％计的化学组成。显然，这些元素与它们各自的经验公式所要求的化学计量含量完全相同。使用场发射扫描电子显微镜观察晶粒的结构形态。图像显示，MoS ₂薄膜由具有许多间隔的大晶粒组成，但是MoS ₂ / Al ₂ O ₃复合材料显示非常光滑的表面，没有任何裂纹或自由空间。此外，通过建立拟合模型并将其计算值与之进行光谱椭圆偏光法研究。计算折射率n，消光系数k，厚度t和吸收系数α。从光的吸收和去极化可以推断出，MoS ₂ / Al ₂ O ₃复合材料是红外区高能量射线的很好吸收剂和低能量射线的很好反射器。MoS _2的光能带隙为2.68 eV，而MoS ₂ / Al ₂ O的能带隙为_3个复合物仍为2.19 eV。