Thermally stimulated current study of space charge formation and contact effects in metal-Polyethylene Terephthalate film-metal systems. I. Generalities and theoretical model
التفاصيل البيبلوغرافية
العنوان:
Thermally stimulated current study of space charge formation and contact effects in metal-Polyethylene Terephthalate film-metal systems. I. Generalities and theoretical model
The Thermally Stimulated Depolarization Current (TSDC) method has been used to emphasize the important role played by the nature of the aluminum-polyester contact on the electrical properties of Metal-Insulator-Metal systems involving thin Polyethylene Terephthalate films (PET) used in capacitors. A progressive change of initially ohmic contacts into blocking ones upon heat treatment has been shown to be responsible for current reversals observed in the space charge region of the TSDC profiles. The use of an electronic band model allowed us to account for the nature and properties of the space charge accumulated in films ranging in thickness from 1.5 to 12 μm. Heterogeneity and retrapping effects have been put forward to explain the difference in behavior observed from ultrathin (1.5 μm thick) to thin films (12 μm thick). It has been shown that the existence of a significant gradient in density of localized states along the thickness of the film gives rise to a significant potential difference between the two vacuum deposited electrodes.
