Frequency-dependent conductivity and capacitance in chalcogenide thin films

The frequency dependence of the capacitance and conductance in Te-As- Ge-Si thin films was measured at various temperatures. When the d.c. component of the conductance is separated, dielectric loss peaks can be found associated with changes in capacitance. In the temperature interval from 225 to 310 K the loss peaks appear at frequencies from 2 to 300 kHz. The activation energy of the corresponding responding relaxation time is about 0.5 eV. At frequencies above 1 MHz a region of highly frequency-dependent conductivity appears with a low temperature sensitivity and without changes in the capacitance. The influence of the increased high frequency conductivity can also be found in the switching dynamics.