IN AND SI DISTRIBUTION IN SYNTHETIC OPALS

An X-ray photoelectric absorption by samples of synthetic opals (SO) l oaded by In and Si has yielded filler distribution profiles over thick ness. The SO+In sample exhibited a uniform filling of SO voids through out the sample thickness (on average, 16.9% of each large void). The S O+Si sample, besides the near-surface region where large voids are com pletely filled, revealed a region with variable Si concentration in th e SO, where the Si content decreases linearly down to a depth where pu re SO is found. (C) 1998 American Institute of Physics.