Influence of temperature and frequency on the AC conductivity and dielectric properties for Ge15Se60Bi25 amorphous films

Thin films of Ge15Se60Bi25 are prepared by thermal evaporation technique on to well cleaned glass substrates. The film thicknesses are measured by quartz crystal monitor method. Thin film capacitors of the type (Al-Ge15Se60Bi25-Al) have been fabricated. The films were well characterized by X-ray diffraction, differential thermal analysis and energy dispersive X-ray spectroscopy. AC conduction and dielectric studies performed on a stabilized samples of thickness range (89.3-214.3 nm) at various frequencies (102-105 Hz) and temperatures (303-413 K). From the AC conduction studies, it is confirmed that the mechanism responsible for the conduction process is hopping. The variations of the dielectric constant and loss as function of frequency and temperature are observed and the results are discussed. Finally, the maximum barrier height Wm and the density of states N(EF) were determined.