Nitrogen dioxide induced conductivity switching in ZnO thin film

作者：Vyas Rishi^*; Sharma Sarla; Gupta Parul; Prasad Arun K; Dhara S K; Tyagi A K; Sachdev K; Sharma S K

来源：Journal of Alloys and Compounds, 2013, 571: 6-11.

DOI：10.1016/j.jallcom.2013.03.217

• Zinc Oxide
• Gas sensing
• Photoluminescence
• Raman spectroscopy

The spin coated ZnO thin films were synthesized and tested for O-2 and NO2 gas detection. It exhibited an increase in resistance i.e. n-type behavior for O-2 exposure (5-20%) and decrease in resistance i.e. p-type behavior for NO2 (2-40 ppm) exposure at operating temperatures of 250 degrees C and 300 degrees C in N-2 atmosphere (0.4 +/- 0.03 mbar). The origin of this aberrant behavior for NO2 exposure was attributed to the participation of defects in NO2 sensing characteristics in light of the data obtained from photoluminescence and Raman spectroscopy studies demonstrating the unique defect morphology of ZnO thin film. The underlying mechanism is discussed on the basis of conclusions drawn from characterization techniques and subsisting knowledge in the literature. The NO2 gas sensing is explained in terms of two competing mechanisms: one is change in charge carrier density on gas exposure as explained by surface depletion model and another is due participation of defects (oxygen vacancies) in gas sensing characteristics.

• 出版日期2013-9-15