The optical and electrical properties and resistance switching of granular films of silver on sapphire

The optical and electrical properties of granular silver films on the surface of sapphire substrates have been experimentally investigated, and measurements have been made during deposition and thermal annealing. The extinction spectra of the granular silver films were measured during deposition. The dependences of the resistance of the films on the final thickness and deposition rate have been established. It is found that the resistance of the films deposited at room temperature continues to change after deposition has ceased, with the character of these changes depending on the rate with which the film was deposited: The resistance increases in films deposited slowly and falls off in those deposited quickly. As a result of annealing at temperatures of the order of 100°C, films deposited at a high rate convert to a high-resistance state, in which they possess distinctive electrical properties: Under a voltage of more than 5 V, their resistance sharply falls off by 5–7 orders of magnitude.