Theoretical study of Si-based ionic switch

We studied the formation/dissolution of a silver (Ag) filament in a silicon (Si) layer through the first-principles calculations. We found these processes take place reversibly by switching the polarity of the bias voltage, bringing about the large resistance change of the Si layer. Furthermore, we developed a model to describe the current-voltage ( I-V ) characteristics for the Ag(electrode)/Si(electrolyte)/p-Si(electrode) switch device and analyzed the experimental result [S. H. Jo and W. Lu, Nano Lett. 8 , 392 (2008)] in the case of using an amorphous Si(a-Si) layer as the electrolyte. It was suggested from the simulated results that dendritic Ag filaments with a fractal dimension of 1.6 are formed in the a-Si layer.