Search

Infrared (IR) antireflective and protective coating (ARPC) is crucial for the development of IR precision guidance and detection systems for practical applications, attracting significant attention from strong military powers worldwide. Extreme application environments require functional film to have high surface hardness, excellent stability, and good adhesion. Further, multispectral optical transmission demands extremely low absorption in the visible and far‐IR bands, adjustability of optical performance parameters, and optical antireflection in particular bands, and radar stealth requires a relatively low resistance. Herein, recent experimental progress on IR ARPC is reviewed and future opportunities are discussed. Based on the application environment and window substrate, various ARPC material systems, including diamond‐like C, Ge carbide, B phosphide, and oxides, have been developed. These systems are capable of fulfilling different application demands and demonstrate exciting application prospects. To promote the development of IR ARPC material technology, the basic characteristics, fabrication techniques, microscale structures, optical properties, mechanical properties, and development and applications of typical IR ARPC materials from a comprehensive and systematic perspective are presented. [ABSTRACT FROM AUTHOR]

Abstract As lanthanum oxide (La 2 O 3) has a large bandgap, it exhibits excellent optical properties. In this work, La 2 O 3 thin films are prepared by the sol-gel method from a lanthanum chloride (LaCl 3) precursor, on quartz and sapphire (0001) substrates. The effect of the annealing temperature (400–800 °C) on the optical properties of the La 2 O 3 films is investigated. The structure and optical properties are analyzed by X-ray diffraction, atomic force microscopy, scanning electronic microscopy, X-ray photoemission spectroscopy, Raman spectroscopy, ultraviolet (UV)–visible spectroscopy, Fourier transform infrared spectroscopy, and infrared variable angle spectroscopic ellipsometry. Results indicate that with an annealing temperature of ~600 °C, the roughness and optical properties of La 2 O 3 films can be significantly improved. Highlights • La 2 O 3 thin films are prepared by sol-gel method on quartz and sapphire substrates. • Effect of annealing temperature on their optical properties is investigated. • Results indicate that the best annealing temperature is around 600 °C. • The roughness and optical properties of films are significantly improved. [ABSTRACT FROM AUTHOR]

The hydrated magnesium-carbon films fabricated in this study are the novel-innovative non-oxide-type transparent electronic material. The films, which have a structure similar to that of magnesium hydroxide, were produced by making Mg x -C y films deposited by magnetron co-sputtering react with water vapor. As the extrinsic defect of hydration magnesium-carbon films, C atoms provided redundant electrons, resulting in a conductivity of approximately 3.31 × 10 −2  Ω·cm. Although the conductivity of hydrated magnesium-carbon films is not prominent comparing to the conventional and widely-used n-type TCO materials, e.g. ITO, the films also showed excellent optical properties, which can be attributed to their low bond energy, with the infrared transmittance of the films being greater than 72% for a plasma wavelength of approximately 10 μm. By varying the atomic C content of the films, a visible-region transmittance greater than 80% could be realized. The optical bandgap of the films was approximately 4.04–6.87 eV and was blue-shifted because of the Moss-Burstein effect. [ABSTRACT FROM AUTHOR]

Highlights: [•] Y2O3:Ru (RYO) films were prepared on ZnS substrates by reactive magnetron sputtering. [•] Ru doping significantly decreases the resistivity and extends the transparent range. [•] Optical and electrical properties of RYO films can be tuned by substrate temperatures. [•] The RYO films exhibit excellent far-IR transmittance and electrical property. [ABSTRACT FROM AUTHOR]

Molybdenum doped zinc oxide thin films have been prepared by RF magnetron sputtering. The influence of the film thickness (120–500 nm) on the structural, electrical, and optical properties of the films is investigated respectively. X-ray diffraction (XRD) studies reveal that with an increase in the film thickness, the crystallinity of the film improves. The obtained film with thickness of 500 nm exhibits the best electrical properties with the lowest resistivity of around 9.6 × 10 −4 Ω cm. The mobility varied from 7.8 to 14.7 cm 2 V −1 s −1 without reducing the achieved high carrier concentration of ∼4.5 × 10 20 cm −3 . Optical band gaps extracted from transmission spectra shows irregular changes due to the Burstein–Moss shift modulated by many-body effects. [ABSTRACT FROM AUTHOR]