Structural features of spin-coated thin films of binary AsS− chalcogenide glass system

Abstract

Spin-coating technology offers a convenient method for fabricating photostable chalcogenide glass thin films that are especially attractive for applications in IR optics. In this paper we report the structure of spin-coated As x S 100 − x (x = 30, 35, 40) thin films as determined using high resolution X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, especially in relation to composition (i.e. As/S ratio) and preparation process variables. It was observed that As atoms during preparation have a tendency to precipitate out in close to stoichiometric compositions. The mechanism of bonding between the inorganic matrix and organic residuals is discussed based on the experimental data. A weak interaction between S ions and amine-based clusters is proposed as the basis of structural organization of the organic-inorganic interface.

Structure and properties of spin-coated Ge_25S_75 chalcogenide thin films

“…Thus we can assume that these new bands have connection with organic molecules content and one or more of them can be attributed to the vibrations of proposed alkyl ammonium germanium sulfide (AAGS) salts molecules. Analogously additional band was already reported in the Raman spectra of spin-coated arsenic-sulfur thin films [16,17] and it was assigned to the vibration of alkyl ammonium arsenic sulfide (AAAS) salts molecules.…”

“…Similarly to the arsenic-sulfur spin-coated thin films [13][14][15][16][17], the Raman spectra of spincoated Ge25S75 samples confirmed thermo-induced structural polymerization connected with decomposition of AAGS salts and releasing the organic molecules. It results in changing of the thin films structure close to the structure of the source bulk glass.…”

“…9) proved, that the chemical stability gradually increases with increasing annealing temperature. According to the literature [16,17] the annealing above the organic salts decomposition temperature also induces significant structural polymerization resulting in more compact thin films. As the organic AAGS salt decomposition temperature was based on SE and EDS measurements expected to be above 120 °C, the chemical stabilization effect of annealing is evident.…”

“…Spincoating and dip-coating deposition methods are frequently used for ChG thin films deposition [12][13][14][15][16][17], but these techniques are suitable only for basic material research and small scale production. Well known and managed printing [18] and coating [19] techniques allowing continuous deposition are gaining attention for large scale production purposes.…”

“…Thin films deposited by solution based techniques have been widely studied on arsenicbased ChGs [12][13][14][15][16][17], which limits their wide-spread application due to the arsenic toxicity. Germanium-based spin-coated thin films of Ge23Sb7S70 glass composition were successfully prepared [20], but further study of other germanium-based systems is needed to obtain plurality of different non-toxic optical materials prepared by solution based deposition techniques.…”