Abstract:
In this work we investigate the electrical and optical properties of Ge15Sb85 thin films prepared by a DC sputtering technique. The phase transition of Te-free films was studied using resistance-temperature measurements. The structure and stoichiometery of the films were identified by X-Ray Diffraction (XRD), and Energy Dispersive X-ray analysis (EDX). The electrical properties of Ge 15Sb 85 films have been investigated using AC conductivity (Impedance spectroscopy). The resistance-temperature measurements reveal that the amorphous-crystalline transition temperature of Ge 15Sb 85 is around T C = 420 K. The optical energy gap of Ge 15Sb 85 films has been measured using UV-VIS-IR spectrophotometer. The estimated activation energy and optical gap allocate the Fermi energy level in high density valence band tail states.