Xref: utzoo sci.energy:3755 sci.electronics:16772 sci.physics:16262 Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!thunder.mcrcim.mcgill.edu!snorkelwacker.mit.edu!usc!wuarchive!udel!berryh From: berryh@udel.edu (John Berryhill) Newsgroups: sci.energy,sci.electronics,sci.physics Subject: Re: solar cells Message-ID: <40997@nigel.ee.udel.edu> Date: 7 Jan 91 22:12:37 GMT References: <1991Jan2.015717.23554@amd.com> <37487@cup.portal.com> <9231@fmeed1.UUCP> Sender: usenet@ee.udel.edu Followup-To: talk.bizarre Organization: University of Delaware Lines: 30 Nntp-Posting-Host: huey.udel.edu In article <9231@fmeed1.UUCP> russ@m-net.ann-arbor.mi.us (Russ Cage) writes: >Widespread use of solar-electric power puts large amounts of all >of these substances into small packages widely spread. Some will >inevitably leak. This is my candidate for nuttiest post so far in the thread. Arsenic doped silicon is in the ppm range and is a constituent of the resulting crystal lattice. It's not going anywhere. Likewise it stays put in GaAs, a chunk of which is sitting on my desk where it's been for months now. At 800C, it will begin to dissociate. I suppose that Russ avoids table salt since it contains Chlorine which we all know is a poisonous gas, because that is exactly analogous to the "leaking" problem that he's crying about. Typical Luddite reaction. As far as the fab processes go, the production of solar cells is not at all comparable to microelectronic circuit fabrication. The toxic organic solvents associated with IC fab arise mainly out of the necessity of the several photolithographic steps needed to define all of the components. A solar cell is a single diode. One diffusion step and then you screen-print the contact. And if you are really worried about the possible release of the gaseous source used for the diffusion (I generally use a 1000 ppm PH3 in He), you can use solid sources which are as safe to handle as the wafers. -- John Berryhill 143 King William Newark, DE 19711