Electrical Switching and Optical Bandgap Studies on Quaternary Ag-Doped Ge-Te-In Thin Films

Amorphous Ge15Te80-xIn5Agx (6 <= x <= 24) thin films prepared in sandwich geometry exhibit memory switching behavior unlike the bulk sample that has shown both threshold switching for less current (1-2mA) andmemory switching for current greater than 2 mA. As anticipated, the threshold voltage of Ge(15)Te(80-x)In5Ag(x)(6 <= x <= 24) thin films is found to be lower as contrast to those of bulk counterparts. The compositional dependence of amorphous system shows an extensive plateau in the range of 6 <= x <= 12 which literally stands for the intermediate phase afterwhich there is a drastic increase in the threshold field. Shifted rigidity percolation threshold has also been confirmed fromthe compositional dependence of threshold field of amorphousGe(15)Te(80-x)In(5)Ag(x) thin films. In addition, the optical bandgap of a-Ge15Te80-xIn5Agx thin-film sample has been reckoned considering absorption spectra, and the compositional dependence has been described based on average bond energy of the system