Compositional dependence of physical parameters in Ge17Se83-xSbx (x = 0, 3, 6, 9, 12, 15) glassy semiconductors

Abstract

Prior investigative studies of physical properties in chalcogenide glasses have gained immense importance in technological [1] and commercial field [2]. Chalcogenide glasses are considered as promising materials for infrared optical elements, infrared optical fibres, information transfer, xerography, switching and memory devices, photolithography, fabrication of inexpensive solar cells and for reversible phase change optical records [3-11]. The GexSe1-x system is of special interest in view of the fact that it forms glasses over a wide domain of composition [12,13]. Addition of third element like As, Sb, Te, In etc. increases the glass forming region as well as creates the compositional and configurational disorder in the system. Since, each impurity may satisfy its valence requirements by adjusting its nearest neighbour’s environment, so it was believed that properties of amorphous semiconductors are weakly affected by the addition of impurities [14], but recently this has been reported that the addition of metal impurities [15] increases the refractive index and lowers the optical band gap significantly. The addition of Sb in the Ge-Se system may change its optical and electrical properties significantly. This stimulated to us to study the Ge-Se-Sb system which varies from floppy mode to rigid mode.