Investigation of Optical Transmission in Thin Metal Films

Thin metal films have recently attracted large interest due to their practical application in photo-detectors, solar cells and quantum electronics. It is known that thin films of noble metals such as Au, Ag, and Cu have a maximum optical transmittance in the shorter part of spectrum.In our work, optical properties of thin metals films deposited by thermal evaporation and low pressure (1.33·10-5 - 1.33·10-4 Pa) DC plasma sputtering were investigated. Such low pressure is provided by triode sputtering method which supports a ballistic type of mass transfer between the sputtering target and the substrate. This method enables fine control of the film thickness and its density. Comparison of the films deposited by mentioned above two methods on glass substrates shows significant differences in their optical and electrical properties. Thin films of following metals: Sn, Al, V, Ti, Ni, Mo, Ta, W, Au, Ag, and Cu were deposited on glass and their optical and electrical properties were studied. The transmission spectra of thin films of various metals have significant differences. In our paper we discuss the causes of these differences.