Electrical Characterization of Hydrothermally Synthesized Manganese Dioxide Nanowires with Regard to NO₂ Adsorption/Desorption Thermodynamics

Abstract

Self-assembled MnO2 nanowires were hydrothermally synthesized and electrically characterized under different conditions. The nanowires were approximately 3–10 µm long and about 20–100 nm in diameter. Single nanowires were aligned perpendicularly across two parallel gold electrode transducers by means of the dielectrophoresis (DEP) technique. Resistivity changes in synthetic air, nitrogen, and NO2 were tested in a range from 100 °C up to 300 °C. The resistivity changes were observed to account for the oxygen reduction on the NWs’ surface as the electrons were moving from the NWs to the oxygen. The resistivity was explored through a constant current arrangement test. Based on the resistivity changes, electrical properties, such as activation energy and type of semiconductor, were estimated.

Keywords

• gas sensing
• nanowires
• manganese dioxide
• nitrogen dioxide
• Arrhenius plot
• defect structure