Transient phenomena and their effect on the insulator barrier in Al-(Al-oxide)-Al structures: T = 100°K

Abstract

When a sufficiently high constant voltage is applied to Al-(Al-oxide, 35 Å)-Al tunnelling structures at low temperatures ( T⪅100°K), the resulting current initially decreases with time and then reaches a stable value. This voltage-induced change of the conductance is practically permanent at T⪅100°K, but can be reversed by warming the sample up to room temperature. For the first time it is shown (by two independent methods) that such transient effects are connected with changes in the height of the insulator barrier. We propose for the voltage-induced transient effects a model based on electron trapping in the insulator. Some of our observations, however, must obviously be attributed to ionic processes.