Space charge limited currents and traps distribution in Ag-As-Te thin films glasses

In this paper, we study the effect of increasing Ag content on the conduction phenomena of AgxAs50-xTe50 with 3 <= x <= 20 glass system with a thickness similar to 150 nm. The current-voltage (J-V) characteristics in the voltage range 0-20 V are measured for all films. The temperature dependence of J-V characteristics are obtained and their results are found to be dependent on the presence of localized state or the trapping levels positioned at a specific energy E-t below the conduction band. Therefore, the charge carrier's concentration in each of the conduction bands, the trapping parameter theta, and the trap density N-t as a function of Ag content are determined. The transition from ohmic to square low behavior has been used to calculate all of these parameters. It has been found that by increasing the Ag at%, the trap activation energy E-t decreases from 0.126 to 0.0739 eV. Therefore, the electron mobility mu(0), effective electron drift mobility mu(e), as well as Fermi level energy E-f, and trapping energy have also been determined. (C) 2009 Elsevier Ltd. All rights reserved.