Selective Oxidation and Carbonization by Laser Writing into Porous Silicon
The selective formation of either oxidized or carbonized features into 2.5 µm thick porous silicon (PS) films using laser writing at a wavelength of 405 nm is demonstrated. Oxidized features are formed in air while carbonized features are achieved during the flow of propane at 600 sccm. Voids wh...
| Main Authors: | , |
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| Format: | Journal Article |
| Published: |
Wiley Online Library
2019
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| Online Access: | http://purl.org/au-research/grants/arc/DP170104266 http://hdl.handle.net/20.500.11937/79810 |
| Summary: | The selective formation of either oxidized or carbonized features into
2.5 µm thick porous silicon (PS) films using laser writing at a wavelength
of 405 nm is demonstrated. Oxidized features are formed in air while
carbonized features are achieved during the flow of propane at 600 sccm.
Voids which have been previously associated with the use of propane are not
observed, largely due to the rapid heating and high flow rates achieved in
the experiment. Carbonized regions with feature widths down to 1.8 µm are
achieved and chemical resistance to both hydrofluoric acid and potassium
hydroxide is demonstrated. Once carbonized regions are formed, the
surrounding areas can be overwritten in air to convert the surrounding
regions into oxidized PS allowing films to be created with as-fabricated,
oxidized and carbonized regions. Energy dispersive X-ray and Raman analysis
confirms the presence of carbon within the written structures. At high
optical powers, cracking around the carbonized features is observed which is
attributed to a contraction of the film. Such cracking is not observed during
selective oxidation of features. This work significantly enhances the ability to
engineer and pattern the composition of PS films enabling selective control of
the material’s properties and functionality. |
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