Reliable current changes with selectivity ratio above 109 observed in lightly doped zinc oxide films

Low-power operation of semiconductor devices is crucial for energy conservation. In particular, energy-efficient devices are essential in portable electronic devices to allow for extended use with a limited power supply. However, unnecessary currents always exist in semiconductor devices, even when the device is in its off state. To solve this problem, it is necessary to use switch devices that can turn active devices on and off effectively. For this purpose, high on/off current selectivity with ultra-low off-current and high on-current is required. Here, we report a novel switch behavior with over 109 selectivity, a high on-current density of 1 MA cm-2, an ultra-low off-current density of 1 mA cm-2, excellent thermal stability up to 250 °C and abrupt turn-on with 5 mV per decade in solution-processed silver-doped zinc oxide thin films. The selection behavior is attributed to light doping of silver ions in zinc oxide films during electrochemical deposition to generate atomic-scale narrow conduction paths, which can be formed and ruptured at low voltages. Device simulation showed that the new selector devices may be used in ultra-highdensity memory devices to provide excellent operation margins and extremely low power consumption. NPG Asia Materials (2017) 9, e351; doi:10.1038/am.2017.5; published online 24 February 2017