Photoinduced changes of the rate of dissolution of bilayer films of chalcogenide glasses

Abstract

The change of the rate of dissolution upon the exposure of bilayer As 39 S 61 /As 36 S 44 Se 20 films to light of wavelength 380 nm and more than 470 nm from the sulfo selenide layer side has been investigated. Although light of wavelength 380 nm is absorbed in the first layer, in the second layer photoinduced structural changes are observed, which are assumed to occur as a result of the diffusion of electron-hole pairs from the illuminated selenium containing layer to the nonexposed arsenic sulfide in contact. The excess charge carriers induce struc tural changes in the As 39 S 61 film that are registered as dissolution rate changes. The calculated value of the drift mobility of the slowest charge carriers (electrons) of 10 -11 cm 2 /(V s) is in agreement with the literature data. Studies of the Raman spectra of the films of interest confirmed that the diffusion of excess electrons and holes into the sulfide layer resulted in structural changes that manifested themselves in a decrease in the intensities and widths of the bands corresponding to vibrations of structural groups containing homopolar bonds.

Identification of artificial orpiment in the interior decorations of the Japanese tower in Laeken, Brussels, Belgium

“…Comparison of the spectra obtained with laboratory-synthetized arsenic sulfide analyzed with Raman spectroscopy (Figure 6b) shows that the pigment used is an arsenic sulfide glass. The different ratios of As 4 S 4 monomer units in its structure (band at 234 cm −1 as well as the shoulder to the main band at 360 cm −1 ) [22,23] between C90.101 (Figure 5c) and the two other cross-sections (Figure 5ab), most likely indicates that the orpiment used has been synthetized following different conditions. Indeed, the Raman bands for the As 4 S 4 monomer units can give an indication on the quenching temperature (Tq); the more important the intensities, the more important the quenching temperature [22].…”