Chalcogenide glasses: preparation, applications, and laser desorption
ionization time-of-flight mass spectrometric study
S. D. Pangavhane1
, J. Havel1,2,3
1
Department of Chemistry, Faculty of Science, Masaryk University, A14/107, Kamenice 753/5, Bohunice,
Brno, (Czech Republic), E-mail: sachin.indiaa@gmail.com
2
Department of Physical Electronics, Masaryk University, Kotlářská 2, 611 37 Brno (Czech Republic), Email:
havel@chemi.muni.cz
3
R&D Center for LowĭCost Plasma and Nanotechnology Surface Modifications, Masaryk University,
Kotlářská 2, 611 37 Brno, Czech Republic
Binary, ternary, or multi-component chalcogenide glasses and their thin films are important for medical
surgery, military, optics, communications, internet, computers, material science, and various
technological applications. Amorphous chalcogenide thin films can be prepared by different deposition
techniques, typically by vacuum thermal evaporation, sputtering, chemical vapour deposition or spincoating.
Pulsed laser deposition is a prospective technique, being employed due to its simplicity, ease of
process control, often stoichiometric transfer of target material to the films and the possibility to fabricate
films of unusual composition. To increase understanding of the properties of thin films fabricated by
plasma deposition techniques, more information concerning the physics of plasma plume is needed. The
formation of clusters in plasma plume from different glasses by laser desorption ionization (LDI) or laser
ablation (LA) was studied by time-of-flight mass spectrometry (TOF MS) in positive and negative ion
modes.
Binary As-Se glass: Several AspSeq singly charged clusters As3Seq
+
(q =1–5), AsSeq
¯
(q =1–3), As2Seq
¯
(q = 2–4), and As3Seq
¯
(q = 2–5) were found from As-Se glasses with the molar ratio As:Se in the range
from 1:2 to 7:3.
Ternary As-S-Se glass: The LA of glasses of different composition leads to the formation of a number
of binary AspSq, AspSer and ternary AspSqSer singly charged clusters. Several series of clusters with the
ratio As:chalcogen = 3:3 (As3S3
+
, As3S2Se+
, As3SSe2
+
), 3:4 (As3S4
+
, As3S3Se+
, As3S2Se2
+
, As3SSe3
+
,
As3Se4
+
), 3:1 (As3S+
, As3Se+
), and 3:2 (As3S2
+
, As3SSe+
, As3Se2
+
), formed from both bulk and pulsed
laser deposited nano-layer of ternary As-S-Se glass, were detected.
Doped glass: Effects of rare earth ions on chalcogenide glasses are intensively studied for several years.
Rare earth ions in optical absorption or light emission exist a direct relation to the energies in ground and
excited states of the electron system. Rare earth-doped chalcogenide glasses due to their strong
luminescence and possible laser action are promising media for potential application in fibre amplifier and
near- and mid- infrared laser devices. We have analyzed erbium doped quaternary Ga-Ge-Sb-S glass and
several series of clusters were identified.
The stoichiometry of AspSeq, AspSqSer, and GalGemSbnSo
+/–
clusters was determined via isotopic envelope
analysis and computer modeling. The stoichiometry of clusters reflects to a certain extend chemical
structure of glasses and thus TOF MS represents suitable experimental technique yielding important
information about glasses chemical structure. The structure of some clusters is proposed and the
relationship to the structure of the parent glasses (As-Se), as also suggested by Raman scattering spectra
was demonstrated.