Negative differential resistance and resistive switching behaviors in Cu2S nanowire devices

Abstract

Two-terminal devices of Cu2S/ZnO core/shell nanowires were fabricated and measured. Forward bias sweeping produced a rectified I-V characteristic of a diode, with turn-on voltages varying from 150 to 300 mV. The turn-on voltages depended on the rate at which the bias was varied. When the bias scan was reversed, a resistive switching (RS) behavior was observed. A low-resistance state was measured, and the diode characteristic diminished. At −50 to −150 mV, negative differential resistance (NDR) was observed, after which the diode behavior was restored. This phenomenon was explained using the diffusion of Cu+ within Cu2S. ZnO acted to limit RS to the positive bias range and NDR to the negative bias range.