The relation of structure and dispersion to amorphous silicon silver thin films

•a-SiAg thin film and Ag/a-Si memristor have similar microstructure and resistivity.•Both refraction index and extinction coefficient rise up at 1300 and 1550 nm.•The optical feathers of Ag/a-Si memristor may be used in optical switch application.

Silver/amorphous silicon (Ag/a-Si) memristor has attracted extensive attention as a candidate for next-generation nonvolatile memories. The optical constant variations of a-Si layer during switching procedure, which are the key for Ag/a-Si memristor to be used in optical applications, have not been clarified yet. To take a further understanding on the optical feathers of Ag/a-Si memristor, here we report the microstructure, resistivity and dispersion relation of amorphous silicon silver (a-Si1−xAgx) thin films prepared by co-sputtering. Ag nanocrystals are observed in the films with size similar to the Ag filament in memristor, and the obtained resistivities of the films march the typical ON/OFF ratio of memristor. Furthermore, both the film's refraction index and extinction coefficient increase with Ag concentration, suggesting that Ag/a-Si memristor combining with silicon waveguide could be applied in optical switch at 1300 and 1550 nm.