Conduction mechanism and the dielectric relaxation process of a-Se75Te25鈭?span style='font-style: italic'>xGax (x=0, 5, 10 and 15xa0;atxa0;wt%) chalcogenide glasses
摘要
Se75Te25鈭?em>xGax (x=0, 5, 10 and 15xA0;atxA0;wt%) chalcogenide compositions were prepared by the well known melt quenching technique. Thin films with different thicknesses in the range (185-630xA0;nm) of the obtained compositions were deposited by thermal evaporation technique. X-ray diffraction patterns indicate that the amorphous nature of the obtained films. The ac conductivity and the dielectric properties of the studied films have been investigated in the frequency range (102-105xA0;Hz) and in the temperature range (293-333xA0;K). The ac conductivity was found to obey the power low 蠅s where s鈮? independent of film thickness. The temperature dependence of both ac conductivity and the exponent s can be well interpreted by the correlated barrier hopping (CBH) model. The experimental results of the dielectric constant 蔚1 and dielectric loss 蔚2 are frequency and temperature dependent. The maximum barrier height Wm calculated from the results of the dielectric loss according to the Guintini equation, and agrees with that proposed by the theory of hopping of charge carriers over a potential barrier as suggested by Elliott for chalcogenide glasses. The density of localized state was estimated for the studied film compositions. The variation of the studied properties with Ga content was also investigated. The correlation between the ac conduction and the dielectric properties were verified.