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Evaluation of GaN and In 0.2 Ga 0.8 N Semiconductors as Potentiometric Anion Selective Electrodes
Author(s) -
Dimitrova Rozalina,
Catalan Lionel,
Alexandrov Dimiter,
Chen Aicheng
Publication year - 2007
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200703936
Subject(s) - electrode , potentiometric titration , electrolyte , ion , materials science , analytical chemistry (journal) , polarization (electrochemistry) , anode , semiconductor , sapphire , inorganic chemistry , chemistry , optoelectronics , optics , chromatography , laser , physics , organic chemistry
The response of potentiometric anion selective electrodes consisting of undoped GaN or In 0.2 Ga 0.8 N films grown on Al 2 O 3 (sapphire) was measured in electrolyte solutions of F − , NO 3 − , Cl − , SCN − , ClO 4 − or Br − anions at concentrations ranging from 10 −6 to 10 −1 M. The slope of the linear regions varied between −32.8 and −51.9 mV/decade for the GaN electrode and between −31.0 and −72.0 mV/decade for the In 0.2 Ga 0.8 N electrode. The drift of the GaN electrode reached 1.57 mV/day in KNO 3 solutions, whereas the drift of the In 0.2 Ga 0.8 N electrode could not be evaluated due to large drops in the slope of its linear range over time. Both electrodes were sensitive to pH variations over the pH range from 12.8 to 1.3. The GaN electrode surface could be electrochemically etched under anodic polarization; however, both GaN and In 0.2 Ga 0.8 N electrodes remained chemically stable and mechanically intact under open circuit conditions even after prolonged use.