Carbon Nanotube Vacuum Gauges With Wide Dynamic Range

• Published in: IEEE transactions on nanotechnology Vol. 8; no. 2; pp. 252 - 257
• Main Authors: Kaul, A.B., Manohara, H.M.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.03.2009; Institute of Electrical and Electronics Engineers
• Subjects: Applied sciences; Carbon nanotube (CNT) pressure sensors; Carbon nanotubes; Chromium; Cross-disciplinary physics: materials science; rheology; Dynamic range; Electrodes; Electron tubes; Electronic equipment and fabrication. Passive components, printed wiring boards, connectics; Electronics; Etching; Exact sciences and technology; Gages; Gauges; General equipment and techniques; Gold; Heat transfer; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; low-power vacuum sensors; Materials science; microcavity pressure sensors; Nanoscale materials and structures: fabrication and characterization; Nanostructure; Nanotubes; Physics; Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing; Substrates; suspended tubes; Thermal conductivity; Transistors; Suspended structure; Measurement sensor; Carbon nanotubes; Thin film resistor; suspended tubes; Pressure sensor; Carbon; Microcavity; low- power vacuum sensors; microcavity pressure sensors; Engraving; Singlewalled nanotube; Silicon oxides; Thermal conductivity; Low-power electronics; Carbon nanotube (CNT) pressure sensors; Thermal conduction
• ISSN: 1536-125X; 1941-0085
• DOI: 10.1109/TNANO.2008.2009534

Carbon-nanotube-based vacuum gauges have been developed and characterized, which primarily utilize the thermal conductivity principle. The vacuum gauges, comprising 5- to 10-mu m-long single-walled nanotubes contacted on either end with Au/Cr electrodes, have been shown to operate at low power (nanowatts to microwatts) and exhibit a wide dynamic range from 760 to 10 -6 torr. Pressure sensitivity was found to increase rapidly as the bias power was increased. In addition, by etching part of the thermal SiO 2 beneath the tubes and minimizing heat conduction through the substrate, pressure sensitivity was extended toward higher vacuums. Results are compared to a conventional thin-film meander resistor, which was fabricated and whose pressure response was also measured for comparative purposes.