Alkali halide crystals, which had been doped with divalent materials such as SnS, SnSe or SnTe, were investigated by means of optical spectroscopy. In the case of SnSe in KCl, it was shown that SnSe molecules replaced pairs of anion and cation vacancies and that samples which were grown from the melt also contained dimers such as (SnSe)2. Annealing at temperatures above 500C resulted in the formation of scattering centers. The latter were believed to be micro-crystals of semiconducting SnSe in an alkali halide matrix.

R.Kamphausen, L.O.Schwan, D.Schmid, J.Degen: Materials Science Forum, 1997, 239-241, 453-6