Pulsed UV laser deposition was exploited for the preparation of thin Sn50-x As x Se50 (x = 0, 0.05, 0.5, and 2.5) films with the aim of investigating the influence of low arsenic concentration on the properties of the deposited layers. It was found that the selected deposition method results in growth of a highly (h00) oriented orthorhombic SnSe phase. The thin films were characterized by different techniques such as X-ray diffraction, scanning electron microscopy with energy-dispersive X-ray spectroscopy, atomic force microscopy, Raman scattering spectroscopy, and spectroscopic ellipsometry. From the results, it can be concluded that thin films containing 0.5 atom % of As exhibited extreme values regarding crystallite size, unit cell volume, or refractive index that significantly differ from those of other samples. Laser ablation with quadrupole ion trap time-of-flight mass spectrometry was used to identify and compare species present in the plasma originating from the interaction of a laser pulse with solid-state Sn50-x As x Se50 materials in both forms, i.e. parent powders as well as deposited thin films. The mass spectra of both materials were similar; particularly, signals of Sn m Se n + clusters with low m and n values were observed.

• Publikační typ
• časopisecké články MeSH

The Ge-Bi-Se thin films of varied compositions (Ge content 0-32.1 at. %, Bi content 0-45.7 at. %, Se content 54.3-67.9 at. %) have been prepared by rf magnetron (co)-sputtering technique. The present study was undertaken in order to investigate the clusters generated during the interaction of laser pulses with Ge-Bi-Se thin films using laser ablation time-of-flight mass spectrometry. The stoichiometry of the clusters was determined in order to understand the individual species present in the plasma plume. Laser ablation of Ge-Bi-Se thin films accompanied by ionization produces about 20 positively and/or negatively charged unary, binary and ternary (Gex+, Biy+, Sez+/-, GexSez+/-, BiySez+/- and GexBiySez-) clusters. Furthermore, we performed the laser ablation experiments of Ge:Bi:Se elemental mixtures and the results were compared with laser ablation time-of-flight mass spectrometry analysis of thin films. Moreover, to understand the geometry of the generated clusters, we calculated structures of some selected binary and ternary clusters using density functional theory. The generated clusters and their calculated possible geometries can give important structural information, as well as help to understand the processes present in the plasma processes exploited for thin films deposition.

• Publikační typ
• časopisecké články MeSH

Amorphous chalcogenide thin films are widely studied due to their enhanced properties and extensive applications. Here, we have studied amorphous Ga-Sb-Se chalcogenide thin films prepared by magnetron co-sputtering, via laser ablation quadrupole ion trap time-of-flight mass spectrometry. Furthermore, the stoichiometry of the generated clusters was determined which gives information about individual species present in the plasma plume originating from the interaction of amorphous chalcogenides with high energy laser pulses. Seven different compositions of thin films (Ga content 7.6-31.7 at. %, Sb content 5.2-31.2 at. %, Se content 61.2-63.3 at. %) were studied and in each case about ~50 different clusters were identified in positive and ~20-30 clusters in negative ion mode. Assuming that polymers can influence the laser desorption (laser ablation) process, we have used parafilm as a material to reduce the destruction of the amorphous network structure and/or promote the laser ablation synthesis of heavier species from those of lower mass. In this case, many new and higher mass clusters were identified. The maximum number of (40) new clusters was detected for the Ga-Sb-Se thin film containing the highest amount of antimony (31.2 at. %). This approach opens new possibilities for laser desorption ionization/laser ablation study of other materials. Finally, for selected binary and ternary clusters, their structure was calculated by using density functional theory optimization procedure.

• Publikační typ
• časopisecké články MeSH

Laser desorption ionization using time-of-flight mass spectrometer afforded with quadrupole ion trap was used to study As2Ch3 (Ch = S, Se, and Te) bulk chalcogenide materials. The main goal of the study is the identification of species present in the plasma originating from the interaction of laser pulses with solid state material. The generated clusters in both positive and negative ion mode are identified as 10 unary (S p+/- and As m+/- ) and 34 binary (As m S p+/- ) species for As2S3 glass, 2 unary (Se q+/- ) and 26 binary (As m Se q+/- ) species for As2Se3 glass, 7 unary (Te r+/- ) and 23 binary (As m Te r+/- ) species for As2Te3 material. The fragmentation of chalcogenide materials was diminished using some polymers and in this way 45 new, higher mass clusters have been detected. This novel approach opens a new possibility for laser desorption ionization mass spectrometry analysis of chalcogenides as well as other materials. Graphical abstract ᅟ.

• Klíčová slova
• Chalcogenides, Clusters, Laser desorption ionization, Structure, Time-of-flight mass spectrometry,
• Publikační typ
• časopisecké články MeSH