Evaluation of GaN and In0.2Ga0.8N Semiconductors as Potentiometric Anion Selective Electrodes

✍ Scribed by Rozalina Dimitrova; Lionel Catalan; Dimiter Alexandrov; Aicheng Chen

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 334 KB
• Volume: 19
• Category: Article
• ISSN: 1040-0397
• DOI: 10.1002/elan.200703936

✦ Synopsis

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 À , NO 3 À , Cl À , SCN À , ClO 4 À or Br À anions at concentrations ranging from 10 À6 to 10 À1 M. The slope of the linear regions varied between À 32.8 and À 51.9 mV/decade for the GaN electrode and between À 31.0 and À 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.