Effects of substrate temperatures on the characterization of magnesium fluoride thin films in deep-ultraviolet region
Effects of substrate temperatures on the characterization of magnesium fluoride thin films in deep-ultraviolet region
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DOI：
10.1364/ao.53.001298
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发表时间：
2014-03-01
期刊：
影响因子：
1.9
通讯作者：
Zhang, Weili
中科院分区：
文献类型：
--
作者：
Sun, Jian;Shao, Jianda;Zhang, Weili
氟化镁（MgF2）是一种广泛应用于深紫外光学系统镀膜的低折射率材料，采用电子束蒸发法在不同衬底温度下制备了MgF2薄膜。研究了基片温度对真空和空气中光学性能、微结构和成分的影响，以及微结构、它们的成分和它们之间的关系。在真空条件下，基片温度直接影响薄膜的微观结构，而薄膜的微观结构决定了薄膜的堆积密度和沿着厚度方向的不均匀性。当薄膜暴露在空气中时，由于薄膜中形成的吸附水和氧化镁（MgO），薄膜的折射率随衬底温度呈非单调的变化趋势。虽然适量的MgO通过减少空位缺陷来减少吸收损耗，但是过量的MgO由于氧化物的高消光系数而增加吸收损耗。(C)2014年美国光学学会
As a low refractive index material widely used in coatings for deep-ultraviolet optical systems, magnesium fluoride (MgF2) films were prepared by electron beam evaporation at different substrate temperatures. The effects of the substrate temperatures on the optical properties in vacuum and in air, microstructures, and composition were investigated, as were the microstructures, their composition, and the relation between them. In vacuum, the substrate temperature directly affected the microstructures which dominated the packing density and inhomogeneity along the film thickness. When the films were exposed to air, the refractive index increased and a nonmonotonic change trend of the refractive index with substrate temperature was observed due to adsorbed water and magnesium oxide (MgO) formed in the film. While a moderate amount of MgO reduced absorption loss by decreasing vacancy defects, excessive MgO increased the absorption loss because of the high extinction coefficient of the oxide. (C) 2014 Optical Society of America