The structure and properties of low temperature deposited durable infrared Ge1-xCx films on As40Se60 chalcogenide glass

In this work, amorphous Ge _1-xC _x films were deposited on As ₄₀Se ₆₀ chalcogenide glass by radio frequency magnetron co-sputtering (rf MS) under low temperature. The deposition temperature rise, the structural, mechanical and optical properties of Ge _1-xC _x films as a function of sputtering power was investigated by thermocouple, X-ray photoelectron spectroscopy (XPS), Raman Spectroscopy, X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Fourier Transformed Infrared Spectroscopy, Surface Profiler, Continuous Stiffness Measurement (CSM) and Environmental Testing Equipment. All the deposition temperature rise of Ge _1-xC _x films generated from radical ions and neutrals decomposed with different sputtering power are mild (<75 °C) and much lower than the transition temperature of As ₄₀Se ₆₀ chalcogenide glass (185 ± 5 °C). The results reveal that C Ge sp ³ hybridization structure decrease, olefinic chains and nc-graphite clusters are transformed to fused aromatic rings, the disorder state and C C sp ³ hybridization structure of amorphous carbon phase increase as sputtering power increases from 50 W to 450 W. Ge atoms are strong nucleation sites for the transformation of olefinic chains and nc-graphite to fused aromatic rings, whereas, highly hydrogenated olefinic chains can inhibit this nucleation function. The nanohardness of Ge _1-xC _x films increases from 4.1 GPa to 12.1 GPa, residual stress of Ge _1-xC _x films transforms from tensile stress to compressive stress, refractive index of Ge _1-xC _x films increases from 2.1 (150 W) to 3.1 (450 W) as sputtering power increases from 50 W to 450 W. Ge _1-xC _x film (150 W) with tensile stress was used as transition layer, consisting of Ge _1-xC _x / Diamond-like Carbon (DLC) double protective antireflective film, which shows excellent adhesion and environmental durability on the surface of As ₄₀Se ₆₀ chalcogenide glass. The average infrared transmittance and nanohardness of As ₄₀Se ₆₀ chalcogenide glass are promoted from 62.2% to 72.6% (3 μm ~ 5 μm) and 1.9 GPa to 7.8 GPa, respectively.