Study of tarnished films formed on silver by exposure to H_2S with the surface-plasmon resonance technique

Abstract

The surface-plasmon resonance (SPR) technique is used to study the growth rate and the nature of Ag(2)S films formed on a silver (Ag) film exposed to an atmosphere containing 50% H(2)S for different times. The thickness of the Ag(2)S layer formed, estimated from shifts in the experimental SPR curves, showed a saturation tendency after an initial linear increase. Theoretical analysis of the curves when Ag and Ag(2)S are treated as two uniform layers and Ag-Ag(2)S as a composite layer showed that radiation damping is mainly responsible for the increase of half-width and dip reflectance, indicating that the Ag(2)S film formed is rough and discontinuous.

The optical response of nanostructured surfaces and the composite diffracted evanescent wave model

“…The disaccord between λ SPP and λ surf is for the present a matter of speculation. Perhaps plasmon "leaky waves" [21] that transport energy very slowly away from the surface contribute to the spectrum of long-range surface excitation resulting in an effective wavelength shift; or perhaps, despite our ellipsometry measurements, the surface index of refraction of the metal film is slightly modified by some uncontrolled chemical or material process [22]. At a more practical level, these results indicate that it might be much easier to couple to surface guided waves than was previously thought.…”

Nanometre-scale electrochemical switches fabricated using a plasma-based sulphidation technique

“…A similar but faster method was considered by Mehan and Mansingh [6], where the silver was sulphidised in a 50% H 2 S atmosphere. These techniques were either too slow or too dangerous for us to use, and also did not involve the use of standard microelectronics processing equipment.…”

“…The goal of each of these fabrication tasks was to create a device as similar to the specifications of Ref [1] as possible, so that differences due to the new SF 6 -based sulphidation could be assessed.…”

Design of an optoelectronic refractometer having an adjustable range of refractive index measurement

“…The refractometers based on interferometry [3,4] and ellipsometry [5] are very sophisticated and elaborate system, a resolution of more than 10 À5 can be achieved by the implementation of such system. The refractometers based on Brewster angle measurement [6], surface plasmon resonance (SPR) [7] and interference microscopy [8,9] are particularly useful for the determination of RI of thin films. Moreover, these systems search for particular position, such as position for minimum reflection in Brewster angle method and the position for resonance in SPR, and hence can never be real-time refractometers.…”