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The gap-type atomic switch is a novel neuromorphic device that possesses functions such as analog changes in resistance and short-term/long-term memory-based learning. However, it is difficult to integrate conventional gap-type atomic switches that use a vacuum gap and Ag2+δS, which has restricted their practical use. In this study, we developed a new, easy to fabricate gap-type atomic switch that incorporates a molecular layer as a gap and Ta2O5 as an ionic transfer material. This molecular gap-type atomic switch operates in a manner that is similar to conventional vacuum gap-type atomic switches. We also demonstrate stochastic operations using the aforementioned molecular gap-type atomic switches. These results indicate a higher potential for the practical use of gap-type atomic switches. [ABSTRACT FROM AUTHOR]

To realize the continuous development of information and communication equipment, it is also important to develop devices with new operating principles that overcome the functional and performance limitations of conventional electronics devices, such as transistors made of semiconductor materials. One group of devices that hold this promise is nanoionics devices that operate by using local ion transport and electrochemical reaction in solids. A number of nanoionics devices that control nanoelectrochemical phenomena through the use of ionic nanoarchitectonics have been created. Here the use of ionic nanoarchitectonics to locally control ion transport and electrochemical reactions through the use of ion conductors or mixed conductors as device materials is described. Further, the structures of nanoionics devices created by using the nanoarchitectonics, as well as their various electrical, magnetic and optical functionalities are introduced. It is expected that such nanoionics devices will complement conventional electronics devices, and make possible the further development of information and communication technologies. [ABSTRACT FROM AUTHOR]

Changes in the resistance of a Ag2+δS nano-island, in which non-stoichiometric δ-Ag atoms work as a dopant in an n-type semiconductor, was induced by electrochemical removal of the dopant δ-Ag atoms using conductive-atomic force microscopy. The removed Ag atoms grew a Ag nanowire on a nano-island, the height of which corresponded to the measured resistance. Conductance (1/resistance) linearly decreased as the height of a Ag nanowire increased, in accordance with the theory of semiconductor conductivity. The technique has the potential for the dynamic control of conductance in nanostructures post-fabrication. [ABSTRACT FROM AUTHOR]

We measured, in vacuum, the temperature dependence of the Forming time in a Ag/Ta2O5/Pt gapless-type atomic switch, the results of which clearly suggest that the rate limiting process is the diffusion of Ag+ cations in the Ta2O5 layer. It is known that water molecules adsorbed in a Ta2O5 matrix enhance the diffusion of Ag+ cations, and this study further shows that desorbing water molecules by annealing at 623 K, which is known to be the desorption temperature of water molecules from Ta2O5 matrixes, increases the diffusion barrier height from 0.38 to 1.1 eV. We found that annealing at much lower temperatures, e.g. 343 K, for a longer period of time can also desorb the said water molecules. Accordingly, we measured the Forming time in air, which resulted in a completely different temperature dependence. The rate limiting process of Forming changes from ionic diffusion to nucleation when the process is conducted in air. [ABSTRACT FROM AUTHOR]