environmental effects on noise in graphene, graphene oxide and carbon nanotube electronic devices
DESCRIPTION
Environmental Effects on Noise in Graphene, Graphene Oxide and Carbon Nanotube Electronic Devices. Brett R. Goldsmith Ye Lu Zhengtang Luo A.T. Charlie Johnson University of Pennsylvania Department of Physics and Astronomy. Sources of Electronic Noise. measuring current noise power - PowerPoint PPT PresentationTRANSCRIPT
Environmental Effects on Noise in Graphene, Graphene Oxide and Carbon
Nanotube Electronic Devices
Brett R. Goldsmith Ye Lu
Zhengtang Luo A.T. Charlie Johnson
University of PennsylvaniaDepartment of Physics and Astronomy
Sources of Electronic Noise
measuring current noise power
Thermal Nyquist noise (~10-24)
Instrument Noise (~10-23)
Telegraph Noise (~10-18)
1/f noise
intrinsic noise
edge states
defects
surrounding environment
Noise Characterization
Noise power is calculated fromthe power spectrum of the current.(using FFT)
b = 1 for most devices
MeasurementsNoise Power: Noise Amplitude:
α(T) = Hooge Constant
N = number of conduction channels SI is given by the power spectrumof the current through the device.
Graphene Electronics
Resistance vs Temperature
measured in a high vacuum chamber, at a rate of 0.1 K/10 seconds
Noise Power vs Temperature - Graphene
Fit for noise power at 1 Hz.
Noise Power also does not change much with temperature
Graphene – Noise Amplitude
Lin, Avouris, Nano Lett., 2008, 8 (8), pp 2119–2125
Noise Amplitude can also be calculated using fit for noise power at 1 Hz
Reduced Graphene Oxide
• Use a strong oxidizer and rapid microwave heating to chemically exfoliate graphite
• Spin cast graphene oxide solution
• Reduce graphene oxide using hydrazine
• We’re using a large film of GO.50 mm
Lou, et. al., J. Am. Chem. Soc., 2009, 131 (3), pp 898–899
Reduced Graphene Oxide
Resistance has a strong temperature dependence.
50 mm
Noise Power vs Temperature
Sharp peaks occur at particular temperatures
Stronger temperature dependence of noise power.
Assigning Noise PeaksLocation of water freezing point vs. Temperature and Pressure
Enhanced noise happens where we expect water to freeze in the vacuum chamber
Noise Amplitude
CNT Network – Noise Amplitude
CNT noise amplitude changes quite dramatically with temperature.
The literature has attributed these types of noise peaks to environmental effects for a few years, even in single tubes.
Kingrey et. al. Nano Lett., 2006, 6 (7), pp 1564–1568
Johnson Group UPenn
Prof. A.T. Charlie Johnson
Ryan Jones
Matthew Berck
Dan Singer
Nicholas Kybert
Thomas Ly
Dr. Zhengtang Luo
Dr. Brett Goldsmith
Dr. Sasa Zaric
Sam Khamis
Bob Johnson
Luke Somers
Ye Lu
Thanks to:IC PostdocDARPAARO
Conclusions:
• Graphene 1/f noise is weakly dependent on temperature
• Reduced graphene oxide 1/f noise shows very strong dependence on temperature and the surrounding environment
• Carbon nanotube 1/f noise is environmentally sensitive.
• Graphene seems to be coupled to it’s surroundings more weakly than carbon nanotubes.