Spectroscopic investigations of glasses with semiconductor microcrystals at higher temperatures

Abstract

Glasses containing microcrystals of CuBr or CuCl show two characteristic absorption peaks caused by excitonic transitions. If temperature is increased the peaks become wider and flatter, whereas the complete disappearance o f the excitonic peaks takes place in a narrow temperature range of 30 to 50 K. Absorption intensity in the UV region (at about 30 000 cm⁻¹) increases simultaneously. The reason for these reversible changes is the melting of the microcrystals about 200 K below the melting point of the corresponding bulk crystals. The melting point depends on size and composition of the microcrystals.