Electrical and optical properties of amorphous Ga2Te3films

Abstract

Ga 2 Te 3 has been prepared in bulk and thin film forms. The composition of films has been checked using energy dispersive X-ray (EDX) spectroscopy technique. X-ray diffraction (XRD) measurements have showed that the Ga 2 Te 3 films evaporated at room temperature substrates were amorphous. Investigation of the I - V characteristics in amorphous Ga 2 Te 3 films reveals that it is typical 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 decreases exponentially with temperature in the range (298−393 K). The switching voltage activation energy ( e ) calculated from the temperature dependence of V th is found to be 0.277 eV. Electrical conduction activation energy () is found to be (0.564 eV). The agreement between the obtained value of the ratio (0.49) and its value derived theoretically (0.5) suggests that the switching phenomenon in amorphous Ga 2 Te 3 films is explained according to an electrothermal model for the switching process. The transmittance ( T ) of Ga 2 Te 3 thin films, has been measured over the wavelength range 400−2500 nm. From an analysis of the transmittance data, the optical constants, the refractive index ( n ) and the extinction coefficient ( k ), have been determined. Similarly the absorption coefficient ( α ) measurements, have been evaluated. Allowed nondirect transitions with optical energy gap () of 1.15 eV have been obtained.