Caractérisation de l'interface métal-diélectrique par l'étude de l'impédance complexe des structures Al/CdS/Au obtenues par pulvérisation cathodique

The interfacial phenomena in sputtered sandwich films were investigated by studying the complex impedance of Al/CdS/Au structures in which the dielectric thickness was less than 800 Å. The experimental results are interpreted using Maxwell-Wagner theory in which the dielectric film is considered as two layers. Semiconductive regions appear when a specific heat treatment is applied. The activation energy associated with conduction variations as a function of temperature is in the range 0.4–1 eV. Comparative studies with restructuring of the aluminium electrode show a correlation between the surface state of the metal and interfacial properties. We show that specific properties of sputtered photocells may be modified by approaching a limit of temperature of 440 K.