Hello all. Just a comment here. I've noticed that when I measure films on Si(100) wafer using 1° incident angle there is very often a wide bump (sometimes superimposed with a narrow peak) at approximately 55°2theta. I'm not quite sure from where it originates, but it usually disappears if sample is rotated or incident angle is changed. (311) isn't too far away though, a sharp peak should be observed at 2-3° incident angle if I've figured it right, so maybe bump is releated to that. The point is that although Iuliana said that one wouldn't probably see anything, I think that on certain parameters the Si can be observed (which is sometimes a nuisance).
I haven't spent too much time trying to figure out the origin of the bump, though, since it usually disappears by rotating the sample and we're dealing with polycrystalline films so rotation doesn't really matter. Anyway, I'd be more than happy if someone here would know the reason for this phenomenon. Regards, Mikko -- Mikko Heikkilä, M.Sc. Laboratory of Inorganic Chemistry Department of Chemistry P.O.Box 55 (A.I. Virtasen aukio 1) FI-00014 University of Helsinki Eduard E. Levin wrote: > Hi Angel, > > I think that such patterns will be of little help to you. If you have a > perfect Si crystal then double diffraction may appear and forbidden > reflections can be seen. Yesterday we discussed with my collegue his > diffraction experiments with Si crystal cut along (100). He said that he > clearly see forbidden (200) reflection, which appears and disappears > when sample rotation is on. > Anyway, even if you will be able to find such patterns you cannot use > them for determination of line position because line shift and > broadenong in asymmetric geometry both depends on grazing angle (c.f. H. > Toraya, J. Yoshino, J. Appl. Cryst 27 (1994) 961). > > Hope this helps. > > Kind regards, > Eduard. > > ----- Original Message ----- From: <alor...@unex.es> > To: <rietveld_l@ill.fr> > Sent: Thursday, April 23, 2009 10:37 AM > Subject: grazing angle diffraction in single-crystal Si > > >> Dear All: >> >> How knows references where I could find the entire diffraction pattern of >> single-crystal Si taken under grazing angle diffraction. >> >> Thanks so much, >> >> Angel L. Ortiz >> >> >> >> >> >> > >
