The silicon used in thin-film cells typically is doped, or nucleated with hydrogen. These typically wind up being nanocrystalline materials as they're applied to a specific task.
But as-deposited amorphous silicon has no detectable cystal structure, at any scale. The standard diffraction method for detecting amorphous materials may be ambiguous at nanoscales, but there is no *positive* indicator for crystal structure in pure amorpous silicon.
This disagrees:
The crystalline structure may simply have been undetectable with your friend's equipment back in the 1980's.
In the 60's the analysis of crystals by X-Ray diffraction needed a dedicated round room with film or detectors at precisely positionable locations on the walls. Constructive interference from the regularly spaced atoms in crystal structures focuses the X-rays into spots on the wall like a prism. Amorphous material just creates diffuse fog.
-jsw
I think there are still amorphous solar cells around. The solar cells in calculators were pretty much all amorphous cells. Cheap, not too efficient, but adequate for calculators.
Dan
Yes, looking around, I see that's one place where they're still used. There also are a variety of experimental multi-layer thin-film cells that contain a layer of amorphous silicon, and which have much higher efficiency. Sony has made some, and there is a large installation of them at an agriculture station somewhere in NJ.
The problem Sony had with theirs, initially, was relatively short life. I don't know if that's still the case.
Ok, I'm certainly not up-to-date on them (or on much else ), so I'll defer.
WAIT a minute. That paper is about hydrogen-doped amorphous/nanocrystalline silicon. It's been known for decades that doping with hydrogen causes amorphous silicon to adopt a nanocrystalline structure.
If that's the evidence, then I think the jury is still out on pure amorphous silicon.
Yep, there are many observations we can't explain because we can't yet measure well enough at the atomic level, especislly below the surface.
That's why I objected to your blanket statement that amorphous silicon has no nanocrystals, in practical mass production versus by theoretical definition. I suspect the solar panel makers don't waste the time and money to check for them, and I once built semiconductor automatic test equipment for Teradyne and was a lab tech at Unitrode.
The surplus monocrystalline panels have degraded in reverse leakage current but not output. At noon they were pushing 85W into the battery according to the power meter.
-jsw
No crystal shape but a crystal. Likely a translation from xxxx to English.
And missed.
Some experimentalist make it out of plastic and other materials.
Mart> >
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