基于纳米胺结构保护层的多波段高反射Ag基膜系制备

Preparation of Multi-Band High Reflectivity Ag-Based Films Based on Nanolaminate Protection Layers

摘要:

Ag基膜系具有在可见到近红外波段最高的反射率,但Ag的环境稳定性较差,易受腐蚀而导致反射率降低。采用离子束辅助电子束蒸发沉积(IAD)方式制备了不同厚度比例的Ta₂O₅-SiO₂纳米胺薄膜,计算出有效折射率和膜层残余应力,选用Ta₂O₅厚度占比为75%的纳米胺薄膜,进一步设计制备了纳米胺结构保护层Ag基膜系和常规两层式结构保护层Ag基膜系,实现了多波段高反射率目标,并且两种Ag基膜系的残余应力相近。在24h湿热实验后,纳米胺结构保护层Ag基膜系的反射率红移量小于常规两层式结构保护层Ag基膜系；在144h湿热实验后,纳米胺结构保护层Ag基膜系表面缺陷腐蚀程度小于常规两层式结构保护层Ag基膜系,结合聚焦离子束制样后利用TEM观察结果,表明纳米胺结构保护层具有更高的致密度,能够为Ag基膜系提供更优良的环境稳定性。

Abstract:

The Ag-based films have highest reflectivity from VIS to IR. However, the environmental stability of Ag thin films is poor and susceptible to corrosion with reflectivity reduction. Different thickness ratio of Ta₂O₅-SiO₂ nanolaminate films were prepared by ion beam assisted electron beam evaporation (IAD). The effective refractive index and residual stress of the films were calculated. Furthermore, the nanoaminate film with Ta₂O₅ thickness percentage of 75% was selected, and the nano-amine structured protective layer Ag-based film system and the conventional two-layer structured protective layer Ag-based film system were further designed and prepared. Multi-band high reflectivity targets were achieved and the residual stress of the two Ag-based films were similar. After 24 hours of humidity test, the reflectance redshift of nanolaminate protection Ag-based films is less than conventional two-layers type protection Ag-based films. After 144 hours of humidity test, the degree of corrosion of the surface defects of nanolaminate protection Ag-based films is less than that of the conventional two-layers type protection Ag-based films. Combined with TEM observation results after combining FIB sample preparation, it is shown that the nanolaminate protection layers possess higher density and can provide better environmental stability for Ag-based films systems.