Gas (H2 and NO2) Sensor of ZnO Nanorods in Vacuum

Vertically-aligned resistive-type ZnO nanorod gas sensors have been successfully fabricated on alumina substrate with a patterned Pt-electrode by using sonochemical method. The responses are characterized by measuring resistance at 250 degrees C in the vacuum chamber where total pressure of 10 torr is maintained and various concentrations of dilute H-2 or NO2 are injected. The gas sensors exhibit the responses of 7 % and 1650 % are respectively at 50 ppm of H-2 and NO2, and increase as gas concentration rises to 1000 ppm. Compared with previous studies conducted at atmospheric pressure, the response to H-2 gas measured at the vacuum is improved, while that to NO2 is similar, promising that ZnO nanorod gas sensors can be developed into high performance gas sensor for vacuum process.