A metal/dielectric ultra-broadband absorption film and its preparation method

Abstract

The invention relates to a metal / dielectric ultra-wideband absorbing film. The metal / dielectric ultra-wideband absorbing film comprises a substrate, a first film and a second film which are sequentially disposed from bottom to top, the first film (2) is a metal / dielectric film stack formed by alternately arranging low-refractive index dielectric films L and high-absorption metal films H, and one side, in contact with the substrate, of the first film is the low-refractive index dielectric film L, and the second film is a single-layer low-refractive index dielectric antireflection film AR. Compared with the prior art, the method omits a traditional thick-layer precious metal substrate, increases the adhesion and the firmness between the film and the substrate, adopts a novel material selection process, realizes an absorption bandwidth of about 7 [mu]m at 400-7000 nm, and makes the obtained film have an average absorption rate of above 92%.

Description

technical field [0001] The invention relates to an optical thin film, in particular to a metal / dielectric ultra-broadband absorption thin film and a preparation method thereof. Background technique [0002] Broadband absorbing thin films have a wide range of applications in photovoltaic cells, photoelectric detection, optical filters, invisibility technology, thermal light source radiation and other fields. Its absorption bandwidth is a key factor affecting its system performance. [0003] At present, there are three main technical approaches to realize broadband absorption films: microstructure films, high absorption black films, and metal / dielectric composite films. Among them, although the microstructured film can achieve broadband absorption, it requires precise etching technology, the preparation process is relatively complicated, and the preparation cost is high, which is not conducive to large-scale industrial production; and for large-sized optical components, the m...

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Problems solved by technology

However, there are defects in these two film structures: first, the problem of metal selection is not solved, and the use of Ni or Ti as the absorbing metal cannot reach the absorption threshold of this structure, resulting in a narrow absorption bandwidth; second, the use of metal Ni is used as a substrate, which limits its application range as an absorber, and Ti is used as a metal substrate for a thin film, which reduces the adhesion and firmness between the thin film and the substrate, and limits its film-forming quality.

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