DC CONDUCTION STUDIES ON TITANIUM-TITANIUM OXIDE-METAL SYSTEMS

The dc conduction data on titanium-titanium oxide-vacuum evaporated me tal (Al, Sn and Sb) systems have been obtained. The effects of field s trength, temperature, thickness of the oxide and the polalrity of elec trode on the dc conduction have been studied. Dominant carrier transpo rt in Ti(+)/TiO2/ metal systems is through Poole-Frenkel conduction me chanism. In Ti(-)/TiO2/metal systems the current-voltage plots show th at at lower voltages charge transfer is through ohmic conduction, howe ver, at higher voltages the slopes of logI-logV plots are in the range of 3.54-3.86, indicating that the space charge limited conduction (SC LC) mechanism is operative. Similar gradual transitions from ohmic con ductivity to SCLC are indicated irrespective of the nature of the meta l and thickness of the oxide film. For Ti (negative electrode), the ga p-state density N(E), are calculated using approaches of Micocci et at [J Appl Phys, 64 (1988) 1885] and Lampert and Mark (1970) for differe nt metals and oxide thicknesses. The values from the two methods compa re well for all the systems. N(E) varies approximately inversely with squared oxide thickness.