Synthesis, Structure and Electronic Properties of Phase Change Material Sb55Se45

Antimony - Selenium (SS) binary alloys have recently gained much attention due to their application in developing phase change random memory (PRAM) devices. In order to understand the electronic and structural properties of this system in detail, we have synthesized bulk Sb55Se45. Energy dispersive x-ray analysis (EDX), ellipsometry and high temperature x-ray diffraction experiments were performed to characterize the samples. The electronic and structural properties are compared with the thinfilm Sb 65Se35 reported earlier. The results of our experiments show that the crystal structure is influenced mainly by the composition and crystallite size. We have observed the bulk Sb55Se45 crystallize in the Sb2Se3 type orthorhombic structure which is different from the rhombohedral Sb2Te type structure reported for the thinfilms. Diffraction measurements show that the orthorhombic structure stable up to temperatures 120°C Further, the results of room temperature Hall mobility and resistivity measurements indicate that this material as p-type. Ellipsometry indicates a refractive index in the range of 2.0 for visible light