A general scheme is described which simplifies the characterization of mixed-crystal semiconductor materials. The scheme is illustrated through the analysis of (Hg1-xCdx)Te samples. Electron microprobe analyses are made at several random points on the material. A plot of the cadmium Lα x-ray intensity vs the mercury Lα x-ray intensity is compared to a stoichiometry line. The scatter of points is a measure of the homogeneity of the material while the correlation of the points with the stoichiometry line indicates the presence of off-stoichiometry material. The stoichiometry line can be theoretically determined or can be obtained using well characterized standard samples. The scheme can best be used on systems which have large composition variations and therefore supplements electrical and x-ray crystallographic methods which are sensitive to minor variations in electrical properties or crystallographic orientations.
James P. Smith and Herbert Kraus, "Electron Microprobe Characterization of the Stoichiometry and Homogeneity of Mixed-Crystal Semiconductor Materials," Appl. Spectrosc. 24, 580-582 (1970)