Electrical and optical properties of amorphous Ga2Te3 films

Ga2Te3 has been prepared in bulk and thin film forms. The composition of fi lms has been checked using energy dispersive X-ray (EDX) spectroscopy techn ique. X-ray diffraction (XRD) measurements have showed that the Ga2Te3 film s evaporated at room temperature substrates were amorphous. Investigation o f the I-V characteristics in amorphous Ga2Te3 films reveals that it is typi cal for a memory switch. The thickness dependence of the mean value of the switching voltage V-th is linear in the investigated range and V-th decreas es exponentially with temperature in the range (298-393 K). The switching v oltage activation energy (epsilon) calculated from the temperature dependen ce of V-th is found to be 0.277 eV. Electrical conduction activation energy (E-sigma) is found to be (0.564 eV). The agreement between the obtained va lue of the ratio epsilon /E-sigma (0.49) and its value derived theoreticall y (0.5) suggests that the switching phenomenon in amorphous Ga2Te3 films is explained according to an electrothermal model for the switching process. The transmittance (T) of Ga2Te3 thin films, has been measured over the wave length range 400-2500 nm. From an analysis of the transmittance data, the o ptical constants, the refractive index (n) and the extinction coefficient ( k), have been determined. Similarly the absorption coefficient (alpha) meas urements, have been evaluated. Allowed nondirect transitions with optical e nergy gap (E-g(opt)) of 1.15 eV have been obtained.