Lin Zesheng, Song Chen, Liu Tianbao, Shao Jianda, Zhu Meiping
Laboratory of Thin Film Optics, Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China.
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China.
ACS Appl Mater Interfaces. 2024 Jun 19;16(24):31756-31767. doi: 10.1021/acsami.4c03747. Epub 2024 Jun 5.
High-performance thin films combining large optical bandgap AlO and high refractive index HfO are excellent components for constructing the next generation of laser systems with enhanced output power. However, the growth of low-defect plasma-enhanced-atomic-layer-deposited (PEALD) AlO for high-power laser applications and its combination with HfO and SiO materials commonly used in high-power laser thin films still face challenges, such as how to minimize defects, especially interface defects. In this work, substrate-layer interface defects in AlO single-layer thin films, layer-layer interface defects in AlO-based bilayer and trilayer thin films, and their effects on the laser-induced damage threshold (LIDT) were investigated via capacitance-voltage (C-V) measurements. The experimental results show that by optimizing the deposition parameters, specifically the deposition temperature, precursor exposure time, and plasma oxygen exposure time, AlO thin films with low defect density and high LIDT can be obtained. Two trilayer anti-reflection (AR) thin film structures, AlO/HfO/SiO and HfO/AlO/SiO, were then prepared and compared. The trilayer AR thin film with AlO/HfO/SiO structure exhibits a lower interface defect density, better interface bonding performance, and an increase in LIDT by approximately 2.8 times. We believe these results provide guidance for the control of interface defects and the design of thin film structures and will benefit many thin film optics for laser applications.
结合大光学带隙的AlO和高折射率的HfO的高性能薄膜是构建具有更高输出功率的下一代激光系统的优异组件。然而，用于高功率激光应用的低缺陷等离子体增强原子层沉积（PEALD）AlO的生长及其与高功率激光薄膜中常用的HfO和SiO材料的结合仍然面临挑战，例如如何最小化缺陷，尤其是界面缺陷。在这项工作中，通过电容-电压（C-V）测量研究了AlO单层薄膜中的衬底-层界面缺陷、AlO基双层和三层薄膜中的层-层界面缺陷及其对激光诱导损伤阈值（LIDT）的影响。实验结果表明，通过优化沉积参数，特别是沉积温度、前驱体暴露时间和等离子体氧暴露时间，可以获得具有低缺陷密度和高LIDT的AlO薄膜。然后制备并比较了两种三层抗反射（AR）薄膜结构，AlO/HfO/SiO和HfO/AlO/SiO。具有AlO/HfO/SiO结构的三层AR薄膜表现出较低的界面缺陷密度、更好的界面结合性能，并且LIDT提高了约2.8倍。我们相信这些结果为界面缺陷的控制和薄膜结构的设计提供了指导，并将有利于许多用于激光应用的薄膜光学器件。
