A vacuum sensor using field emitters made by multiwalled carbon nanotube yarns

A newly developed vacuum sensor using carbon nanotube (CNT) field-emission has been designed. The fabricated device is an ionization gauge with a silk-like CNT yarn cathode, and the vacuum is indicated by the ratio of the ion current to the electron-emission current. The metrological characteristics of the sensor were studied in a dynamic vacuum system. It showed good linearity ranged from 10−4 to 10−1 Pa. Taking advantage of the field-emission cathode, the power consumption is only about 5.5 mW. Moreover, comparing it to the conventional thermionic cathode, the CNT yarn cathode is more miniature and a cold cathode with no obvious thermal outgassing effect. Due to these features, the sensor described here could have potential applications in measuring vacuum inside sealed and miniaturized devices.

► A vacuum sensor using carbon nanotube yarn field-emission.
► Stable normalized ion current with a variation about ±10%.
► Good linearity in the range from 10−4 Pa to 10−1 Pa even up to 10 Pa.
► Features of low power consumption, compact structure, and no obvious outgassing.
► Potential application in measuring vacuum inside sealed and miniaturized device.