Kirchhoff’s Thermal Radiation from Lithography-Free Black Metals

Lithography-free black metals composed of a nano-layered stack of materials are attractive not only due to their optical properties but also by virtue of fabrication simplicity and the cost reduction of devices based on such structures. We demonstrate multi-layer black metal layered structures with...

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Bibliographic Details
Main Authors: Takuhiro Kumagai, Naoki To, Armandas Balčytis, Gediminas Seniutinas, Saulius Juodkazis, Yoshiaki Nishijima
Format: Article
Language:English
Published: MDPI AG 2020-08-01
Series:Micromachines
Subjects:
Online Access:https://www.mdpi.com/2072-666X/11/9/824
Description
Summary:Lithography-free black metals composed of a nano-layered stack of materials are attractive not only due to their optical properties but also by virtue of fabrication simplicity and the cost reduction of devices based on such structures. We demonstrate multi-layer black metal layered structures with engineered electromagnetic absorption in the mid-infrared (MIR) wavelength range. Characterization of thin <inline-formula><math display="inline"><semantics><mrow><msub><mi>SiO</mi><mn>2</mn></msub></mrow></semantics></math></inline-formula> and Si films sandwiched between two Au layers by way of experimental electromagnetic radiation absorption and thermal radiation emission measurements as well as finite difference time domain (FDTD) numerical simulations is presented. Comparison of experimental and simulation data derived optical properties of multi-layer black metals provide guidelines for absorber/emitter structure design and potential applications. In addition, relatively simple lithography-free multi-layer structures are shown to exhibit absorber/emitter performance that is on par with what is reported in the literature for considerably more elaborate nano/micro-scale patterned metasurfaces.
ISSN:2072-666X