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

View Article: PubMed Central - PubMed

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.

No MeSH data available.


(a) SEM image of the sample after four repeated etching steps using resist and SiO2 interlayer as a mask. The etching depth is set to 100 nm for each step. (b) SPM image of the sample after six repeated etching steps using resist and SiO2 interlayer as a mask. The depth of 490 nm is obtained.
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Figure 4: (a) SEM image of the sample after four repeated etching steps using resist and SiO2 interlayer as a mask. The etching depth is set to 100 nm for each step. (b) SPM image of the sample after six repeated etching steps using resist and SiO2 interlayer as a mask. The depth of 490 nm is obtained.

Mentions: The micro-holes fabricated by the multi-step etching process are shown in figure 4. A scalloped pattern in the walls of the micro-holes was observed by SEM (figure 4(a)). The depths of the holes can be found in the SPM image shown by figure 4(b). A depth of 490 nm can be obtained by six etching steps.


Anisotropic multi-step etching for large-area fabrication of surface microstructures on stainless steel to control thermal radiation
(a) SEM image of the sample after four repeated etching steps using resist and SiO2 interlayer as a mask. The etching depth is set to 100 nm for each step. (b) SPM image of the sample after six repeated etching steps using resist and SiO2 interlayer as a mask. The depth of 490 nm is obtained.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5036480&req=5

Figure 4: (a) SEM image of the sample after four repeated etching steps using resist and SiO2 interlayer as a mask. The etching depth is set to 100 nm for each step. (b) SPM image of the sample after six repeated etching steps using resist and SiO2 interlayer as a mask. The depth of 490 nm is obtained.
Mentions: The micro-holes fabricated by the multi-step etching process are shown in figure 4. A scalloped pattern in the walls of the micro-holes was observed by SEM (figure 4(a)). The depths of the holes can be found in the SPM image shown by figure 4(b). A depth of 490 nm can be obtained by six etching steps.

View Article: PubMed Central - PubMed

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.

No MeSH data available.