Microstructure and properties of La-doped Er2O3 anti-reflection films on CVD diamond

• Published in: Applied surface science Vol. 602; p. 154229
• Main Authors: Huang, Yabo, Zhu, Xiaohua, Cao, Shuqin, Chen, Liangxian, Shao, Siwu, An, Kang, Zheng, Yuting, Liu, Jinlong, Wei, Junjun, Li, Chengming
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.11.2022
• Subjects: Composition; CVD diamond, La-doped Er2O3 antireflective films; Properties; Properties; Composition; CVD diamond, La-doped Er2O3 antireflective films
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2022.154229

[Display omitted] •The La-doped Er2O3 anti-reflection films was prepared by the power of magnetron sputtering.•The compound of La2O3 formed along the grain boundary of the columnar crystal structure of the polycrystalline film.•The highest hardness and yield strength of the La-doped Er2O3 film was two times higher than that of pure Er2O3 film.•The transmittance of the La-doped Er2O3 anti-reflection films only decreased 1% after erosion. The composition and microstructure consisting of anti-reflection films was obtained by the power of magnetron sputtering. X-ray photoelectron spectroscopy (XPS) and High-resolution transmission electron microscopy (HRTEM) provided evidence to support that the doping La element exists as oxide in the grain boundaries of the matrix Er2O3 films. The undoped and La-doped Er2O3 films show a columnar crystal structure of the main cubic (222) plane. Twinning and a large number of dislocations show up in the undoped Er2O3 films due to the competitive growth of the columnar crystal. In addition, the La-doped Er2O3 films show a lower roughness (RMS) value in comparison with undoped Er2O3 films. The grain size of columnar crystals decreases significantly with increasing La concentration in the La-doped Er2O3 films. The fine grains resulted in the La-doped Er2O3 films developing high mechanical and impact resistance properties, with an increase in hardness from 12.6 ± 2.1 GPa to 26.1 ± 3.4 GPa and the eroding area rate decreasing from 38.9 % to 1.9 %. Moreover, the La-doped Er2O3 anti-reflection films on the chemical vapor deposition (CVD) diamond substrate maintained 74 % transmittance in the long-wavelength infrared range of 8–12 μm after sand eroding.