Anisotropic multi-step etching for large-area fabrication of surface microstructures on stainless steel to control thermal radiation

Abstract

Controlling the thermal radiation spectra of materials is one of the promising ways to advance energy system efficiency. It is well known that the thermal radiation spectrum can be controlled through the introduction of periodic surface microstructures. Herein, a method for the large-area fabrication of periodic microstructures based on multi-step wet etching is described. The method consists of three main steps, i.e., resist mask fabrication via photolithography, electrochemical wet etching, and side wall protection. Using this method, high-aspect micro-holes (0.82 aspect ratio) arrayed with hexagonal symmetry were fabricated on a stainless steel substrate. The conventional wet etching process method typically provides an aspect ratio of 0.3. The optical absorption peak attributed to the fabricated micro-hole array appeared at 0.8 μm, and the peak absorbance exceeded 0.8 for the micro-holes with a 0.82 aspect ratio. While argon plasma etching in a vacuum chamber was used in the present study for the formation of the protective layer, atmospheric plasma etching should be possible and will expand the applicability of this new method for the large-area fabrication of high-aspect materials.

A High-Temperature Solar Selective Absorber Based upon Periodic Shallow Microstructures Coated by Multi-Layers Using Atomic Layer Deposition

“…Honeycomb-arrayed periodic patterns were fabricated on the resist mask by three-beam interference lithography using Mach-Zehnder type optics [26]. The conditions of the interference lithograph were used as stated in the previous report [27]. After the lithography process, the resist pattern was transferred onto the W substrate by conducting a dry etching process with fast ion beam (FAB) etching.…”

Route to High-Performance Micro-solid Oxide Fuel Cells on Metallic Substrates

“…Further improvements in the process are highly possible using several-step etching procedures. 37 Moreover, the film growth techniques demonstrated in this work could readily be implemented on novel substrates, for instance, nanoporous Ni, on which virtually pore-free electrolytes can be deposited by PLD, thus allowing gas access without the need for etching and further enhancing the commercial applicability of this work. 2 , 37 …”

“…The disadvantage in this case is the isotropic nature of the etch. This can be mitigated by adopting a three-step procedure as demonstrated by Shimizu et al, though to date this has only been applied to much thinner substrates ~500nm) [37]. Samples were etched for approximately five hours at 70° C and stirred at 60 rpm for the first four hours.…”

“…Further improvements in the process are highly possible using severalstep etching procedures [37]. Moreover, the film growth techniques demonstrated in this work could readily be implemented on novel substrates, for instance nanoporous Ni, on which virtually pore-free electrolytes can be deposited by PLD, thus allowing gas access without the need for etching and so further enhancing the commercial applicability of this work [2,37]. Having demonstrated the growth of mesoporous VAN cathodes on both single-crystal and metal substrates and the ability to etch holes in the stainless steel substrate, we now turn to the electrical performance of the films.…”

Fabrication of Functional Plastic Parts Using Nanostructured Steel Mold Inserts

“…Landolt et al made comprehensive reviews on the effect of the main parameters affecting electrochemical etching for titanium and stainless steel surfaces [ 25 , 26 , 27 ]. Usually limited to an isotropic profile, electrochemical etching has also been used in a sequential Bosch-like process to create higher aspect ratio structures, as reported by Shimizu et al [ 28 ]. Finally, physical etching techniques have also been used for the fabrication of nanostructured steel surfaces.…”