Devitrification Characteristics of the Semiconductor System (1 − x)As[sub 2]Se[sub 3] [middle dot] xSb[sub 2]Se[sub 3]

The devitrification kinetics in the system ( 1 − x ) As 2 Se 3 · x Sb 2 Se 3 were studied as a function of temperature (69°–183°C) and composition ( x = 0.1 – 0.5 ) . The activation energy of the linear growth rates of relatively large rectangular platelet‐like crystals in the vitreous matrix was found to be 38 kcal/mole for x = 0.1 and 50 kcal/mole for x = 0.3 , 0.4 , and 0.5. Along the long dimension of the platelets the growth rate was found to be three times greater than that along the short dimension. Along this long dimension the growth rate increased about three orders of magnitude in going from x = 0.1 to x = 0.5 . The number of crystals formed in the vitreous matrix per unit area increased with increasing Sb 2 Se 3 content. The chemical composition of the crystals formed by devitrification was found to be different than that of the surrounding matrix. Quantitative electron microprobe analysis and scanning electron microscopy showed that the Sb content was higher in the crystals than in the surrounding matrix. Crystals grown directly from the melt (by slow cooling) were even richer in Sb than the neighboring matrix. X‐ray diffraction results showed that the materials with low Sb 2 Se 3 content crystallized in the system of As 2 Se 3 (monocline) whereas materials relatively rich in Sb 2 Se 3 crystallized in the Sb 2 Se 3 system (orthorhombic). In alloys of intermediate composition both systems were present. In materials in which the monoclinic structure predominated the devitrification rates and the associated activation energies were found to increase with the Sb 2 Se 3 content; whereas they were composition independent in materials in which the orthorhombic structure predominated.