Am Freitag, den 19.02.2010, 11:21 +0100 schrieb Huy LE-QUOC: > Dear Rietvelders, > > To avoid the gigantic peaks of Si substrate (which are too dominant over > peaks of phases in investigation on a thin film of 3 micron), we have > tried to take a scan theta-two theta with a shift of 3 degree for theta > (i.e. instead of theta-2theta corresponding to 5-10 degree at the > beginning, I have set theta=8 degree and 2theta=10). In fact, we have > been able to reduce dramatically intensity of Si peaks but the > broadening of all peaks in the diffractogram is increased comparing to > the "normal" scan without shift of theta. > > We have also tried to rotate the sample around its perpendicular axis > (angle Phi) to find the appropriate Phi where the peaks of Si are > slightly decreased and found that the broadening of peaks is the same as > in a "normal" theta-2theta scan. > > Does anyone have any ideas about this increased broadening of peaks > during a theta-2theta scan with theta shifted ? The Theta-Theta-geometry is a method for focussing X-Rays, you will loss the focus by rotating the sample off the theta-theta set-up. There are available special cut Si plates with a surface normal avoiding all possible reflections.
Joerg > By the way, do you know others ways, besides the razing incidence, to > avoid the dominant peaks of substrate over the thin film ? > > Thanks a lot in advance for your any helps. > > Best regards, > > --- > Huy LE-QUOC, > Doctorant > LPSC/UJF-Grenoble INP-CNRS, Centre de Recherche > Plasmas-Matériaux-Nanostructures > Institut Néel/CNRS, Département "Matière Condensée, Matériaux et Fonctions" > 53 rue des Martyrs, Grenoble 38026, FRANCE > Phone: +33 4 76 28 40 38 > Fax: +33 4 76 28 40 11 > > >
