Structural elucidation of AgAsS 2 glass by the analysis of clusters formed during laser desorption ionisation applying quadrupole ion trap time‐of‐flight mass spectrometry

Rationale The structure of AgAsS 2 glass, which has a broad range of applications, is still not well understood and a systematic mass spectrometric analysis of AgAsS 2 glass is currently not available. Elucidation of the structure should help in the development of this material. Methods The AgAsS 2 glass was prepared by the melt‐quenched technique. Laser desorption ionisation (LDI) using quadrupole ion trap time‐of‐flight mass spectrometry (QIT‐TOFMS) was used to follow the generation of Ag m As n S x clusters. The stoichiometry of the clusters generated was determined via collision‐induced dissociation (CID) and modelling of isotopic patterns. The AgAsS 2 glass was characterised by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive X‐ray (EDX) spectroscopy. Results The LDI of AgAsS 2 glass leads to the formation of unary (Ag +/− and As 3 + ) species, 38 binary (As n S x , Ag m S x ), and 98 ternary (Ag m As n S x ) singly charged clusters. The formation of silver‐rich nano‐grains during AgAsS 2 glass synthesis has been identified using TEM analysis and also verified by QIT‐TOFMS. Conclusions TOFMS was shown to be a useful technique to study the generation of Ag m As n S x clusters. SEM, TEM and EDX analysis proved that the structure of AgAsS 2 glass is ‘grain‐like’ where grains are either: (1) Silver‐rich ‘islands’ (Ag m , m up to 39) connected by arsenic and/or sulfur or arsenic sulfide chains or (2) silver sulfide (Ag 2 S) m ( m  = 9–20) clusters also similarly inter‐connected. This obtained structural information may be useful for the development of ultra‐high‐density phase‐change storage and memory devices using this kind of glass as a base. Copyright © 2016 John Wiley & Sons, Ltd.