(A) Schematic cross section of the Berkeley Lab High Frequency Abacus Nanotube Resonator. An evaporation of materials such as indium onto the carbon nanotube forms an abacus-like structure of moveable beads along the nanotube.
(B) Scanning electron micrograph of indium beads on a carbon nanotube.
APPLICATIONS OF TECHNOLOGY:
- Filter or amplifier for microwave frequency and RF electronics, e.g. cell phones, personal music devices
- Mass sensor
- Frequencies over 4 GHz
- Operates at ambient temperatures and pressures without significant loss of resonance quality
- Individually tunable, post-production
- Capable of mass detection with molecular resolution (10-18g)
Various bottom-up and top-down fabrication processes have been used to create resonating NEMS devices but none have achieved ultrahigh frequency (>1 GHz) operation at room temperature in atmospheric pressure while maintaining adequate resonance quality. Alex Zettl and Haibing Peng of Berkeley Lab are the first to develop such a resonator, which has promising commercial applications in microwave and radio frequency electronic devices and could be used as a ultra-high sensitivity mass sensor.
The Berkeley Lab resonator consists of carbon nanotubes (CNTs) grown across trenches etched in silicon chips with the ends of the nanotubes connected to source and drain electrodes. Gate electrodes deposited in the bottom of the trenches allow for capacitive coupling to the nanotube. The invention employs a new combination of drive and detection methods that enables unprecedented measurement of both oscillation amplitude and phase. The resonator can be tuned after production by moving bead clamps along the nanotube using a novel mass transport method, also developed in the Zettl lab, much like a guitar string is tuned using finger pressure.
Scaling down the CNT-based resonator and selecting suitable coating materials may achieve resonance frequencies well over 10 GHz. Other materials such as nanowires and nanorods may be substituted for the carbon nanotubes.
- Published PCT Patent Application WO2008/049122 available at www.wipo.int. Available for licensing or collaborative research.
FOR MORE INFORMATION:
REFERENCE NUMBER: IB-2330
SEE THESE OTHER BERKELEY LAB TECHNOLOGIES IN THIS FIELD:
- Nanoresonator for Precise Positioning and Mass Sensing, IB-2124
- Voltage-Controlled, Autotransducing Microwave Oscillator, IB-2008
- Controllable, Reversible, Nanoscale Mass Conveyor, IB-2007