Investigation of Surface Plasmon Dispersion
Abstract
The attenuated-total-reflection (ATR) technique was used to study surface plasma wave (SPW) dispersion of Cs- and Cs-O-covered Ag surfaces. Our data indicate that SPW are heavily damped by an adsorbed Cs submonolayer with no obvious change in their wavevectors. However, in the presence of an adsorbed Cs- O submonolayer, SPW show changes in their wavevectors, but without any obvious damping. Based on our theoretical analysis, we have concluded that the Cs-Ag and the Cs-O-Ag surface layers are strongly absorptive and transparent, respectively. The relationship between the SPW damping and Cs coverage indicates that SPW can be damped by a photoelectric effect. A least-squares fit for the ATR data was used to determine the optical constant e = e' + ie'' and thickness, d, of Ag films thinner than 600 A. We found two sets of e and d from the fitting for each wavelength that can be distinguished by simultaneously fitting data for another wavelength. For a slowly deposited Ag film with mass thickness t smaller than 250 A, we found that, for decreasing t (1) the derived e' becomes less negative, (2) e'' increases dramatically, and (3) the derived effective thickness is about 200 A, which suggests that the Ag films are more likely to be island types with an island height of approximately 200 A. SPW were also used to enhance photoemission signals from a cathode and to enhance the photovoltaic signal from a Si-Au diode.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 30, 1980
- Accession Number
- ADA091853
Entities
People
- Jar-mo Chen
- Wenpeng Chen
Organizations
- Martin Marietta