Voltage- and temperature-dependent electrical behavior of gap-type Ag–Ag2S–Pt atomic switch

Abstract

The voltage- and the temperature-dependent electrical behavior of a gap-type Ag–Ag2S–Pt atomic switch is theoretically investigated. The electrical tunnel current passing through the switch is calculated and the growth of Ag nanowires between two electrodes is simulated. Our calculations show the switching time (the time that is required to decrease the resistance of switch below the resistance quantum RQ ≈ 6.5 kΩ) exponentially decreases as the applied voltage increases that agrees very well with experimental findings. Furthermore, we assumed the Ag2S layer is a few atomic layer thick so the diffusion time of Ag+ ions within the Ag2S layer can be neglected compared to the formation of Ag nanowires. As a result, the switching time decreases exponentially as temperature increases. The switching time is calculated while different DC voltages are applied to the switch over temperature range of T = 300–350 K. The results imply both of the voltage- and the temperature-dependent behavior of the gap-type Ag–Ag2S–Pt atomic switch is dominated by the Coulomb blockade (CB) effect of Ag nanowires as electrons require energy to overcome the CB energy of Ag nanowires to sustain the growth of Ag nanowires.