Analog resistive-switching property of Ni/TiOx/W structure

A radio-frequency magnetron sputter was used to deposit a 60 nm TiOx film on a W-coated Si substrate at room temperature. Subsequently, a 100 nm Ni film was deposited using a thermal evaporator to form a Ni/TiOx/W structure. Numerous oxygen vacancies and defects were present in the TiOx film. The current-voltage characteristics indicate that Schottky emission dominated the conduction mechanism of the Ni/TiOx/W structure. Because of Schottky barrier modulation, analog resistive switching of the Ni/TiOx/W structure can be performed using consecutive voltage sweepings or voltage pulses. Various pulse waveforms were used to demonstrate synaptic potentiation and depression.