A quick search online and I found this about RIE etching of copper using HCL gas.
http://yuekuo.tamu.edu/Rie.htm Have a look at the 3rd SEM micrograph down which compares exposing copper to HCL gas vs. HCL plasma. The one on the right (plasma etch) shows surface topography in the micron to sub micron range. this is the condition I was looking for on my silicon etch experiments. I have a hunch that careful optimization of process parameters such as temperature, pressure, plasma density, bias voltage, and perhaps the introduction of a specific contaminant to the gas can result in anisotropy and densification of these structures. This means that it would not be necessary to sputter silicon to get my motheye film but it could be etched directly on the copper pipe. As kirk pointed out copper has low emissivity and if we can get 60% absorbance per hit it might be really viable. :) Joe Joe Street wrote: > What I did is the same idea but instead of blades stacked with thier > edges facing you picture needles on a nano scale. Blades are effective > on one axis. Needles on two axes. > > J > > Kirk McLoren wrote: > > >>Laser targets look like a stack of razor blades. Multiple reflections >>and absorbance at each juncture. I once penciled a z fold with 20 degree >>aperture and made of polished copper would look as good as a black >>selective surface receiver. The polished copper has low emittance but >>even though absorbance was around 60% It was quite high after multiple >>reflections. As your aperture closes # of hits (or bounces if you >>prefer) become higher and higher. >>Kirk >> >>*/Mike Redler <[EMAIL PROTECTED]>/* wrote: >> >> Hi Joe, >> >> Your research is a little outside of my range of expertise. So, I gave >> your message to my finance. She has a PhD in Chemistry and runs a >> chromatography lab. >> >> All she had to say was "Wow! He's got access to some nice >> equipment.". I >> think she's jealous. >> >> I may be way off but, your description reminds me of black anodize. >> >> Anyway, it looks promising. >> >> Good luck. >> >> -Redler >> >> >> Joe Street wrote: >> > Hi Mike; >> > >> > I don't have any references I can recommend but I'll tell you what I >> > did. I dry etched silicon using flourine ions in a reactive ion >> etcher. >> > Making use of native polymer contamination of the surface and >> carefully >> > controling the presence of oxygen radicals I was able to form a >> dense >> > structure of columns roughly 100 nm wide and 400 nm tall that when >> > viewed with an electron microscope look something like a forest. The >> > nanoconvolution of the surface on a scale less than the >> wavelength of >> > visible light results in an extremely antireflective black surface >> > similar to a moth's eye. (BTW this is why moths see so well in >> the dark) >> > The silicon material absorbs all the incoming radiation in the >> visible >> > and longer wavelengths and even most of the ultaviolet I'd guess >> as low >> > as 198 nm although I haven't tested it. Silicon is roughly >> similar to >> > iron in its heat conducting properties so this film would be very >> good >> > for a passive solar system. I think I could build a machine to >> sputter >> > silicon on pipes and etch it in situ if I had the resources. >> > >> > Joe >> > >> > Mike Redler wrote: >> > >> > >> >> Hi everyone, >> >> >> >> I know of some descent resources for electronic circuits, software >> >> development, and a bunch of other stuff. However, I've come up with >> >> nuthin' for black bodies which contains both a practical guide for >> >> passive solar collection and the analytical/mathematical tools for >> >> theoretical modeling. Once I have that, I'm good to go, already >> having >> >> one pretty good general text on heat transfer (J.P. Holman, >> seventh ed.). >> >> >> >> Joe, I know you mentioned some work you did with thin films (if my >> >> memory serves me right). >> >> >> >> Can anyone point to a good on-line source? I'd even be happy with a >> >> textbook recommendation. >> >> >> >> -Redler >> >> _______________________________________________ >> Biofuel mailing list >> Biofuel@sustainablelists.org >> http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org >> >> Biofuel at Journey to Forever: >> http://journeytoforever.org/biofuel.html >> >> Search the combined Biofuel and Biofuels-biz list archives (50,000 >> messages): >> http://www.mail-archive.com/biofuel@sustainablelists.org/ >> >> >>__________________________________________________ >>Do You Yahoo!? >>Tired of spam? Yahoo! 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