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Laser desorption ionization time‐of‐flight mass spectrometry of Ge‐As‐Te chalcogenides
Author(s) -
Šútorová Katarína,
Hawlová Petra,
Prokeš Lubomír,
Němec Petr,
Boidin Rémi,
Havel Josef
Publication year - 2015
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.7120
Subject(s) - chemistry , mass spectrometry , time of flight mass spectrometry , ionization , laser , desorption , germanium , analytical chemistry (journal) , chromatography , ion , optics , organic chemistry , adsorption , physics , silicon
Rationale Ge x As y Te z glasses have a broad window of optical transparency and high refractive index which make them promising for applications in the infrared region. The aim of this work is to reveal structural motifs which could be present during the fabrication of Ge‐As‐Te thin films by plasma deposition techniques; such knowledge is important for the optimization of thin film growth. Methods Mass spectra were acquired using a laser desorption ionization time‐of‐flight (LDI‐TOF) mass spectrometer equipped with a nitrogen laser (337 nm) coupled with a quadrupole ion trap, and recorded in positive and negative ion reflectron modes. XRD, SEM (EDX) and Raman spectroscopy were also used for the characterization of Ge‐As‐Te bulk or powdered samples. Results Bulk Ge x As y Te z samples ( x = 10–20%, y = 20–60%, z = 30–70%) were synthesized. LDI‐MS of Ge‐As‐Te powders provided evidence for the formation of both positively and negatively charged clusters, whose stoichiometry was determined as Te n +/– ( n = 1–4), Te 5 + , binary AsTe n +/– ( n = 1–3), GeTe n +/– ( n = 1–3), As 2 Te +/– , As 2 Te 3 + , As 3 Te + , AsTe 4 + , Ge 2 H 6 +/– , ternary GeAsTe + , GeAsTe 2 +/– , GeAsH 5 + , GeAsH 6 + , GeAsH 12 + , and tertiary GeAsTeH 5 – , GeAsTeH 8 – , GeAsTe 2 H 3 +/– . Conclusions The local structure of Ge x As y Te z materials is at least partly different from that of species identified in plasma by mass spectrometry, as deduced from Raman scattering spectroscopy analysis. However, LDI‐TOFMS was found to be a suitable technique for the partial structure characterization of Ge‐As‐Te bulk samples and especially for the identification of the structural motifs present in the plasma during the preparation of the corresponding thin films. Copyright © 2015 John Wiley & Sons, Ltd.