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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
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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
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Noise Characterization
Noise power is calculated from the power spectrum of the current. (using FFT) b = 1 for most devices
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Measurements Noise Power: Noise Amplitude: α(T) = Hooge Constant
N = number of conduction channels SI is given by the power spectrum of the current through the device.
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Graphene Electronics
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Resistance vs Temperature
measured in a high vacuum chamber, at a rate of 0.1 K/10 seconds
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Noise Power vs Temperature - Graphene
Fit for noise power at 1 Hz. Noise Power also does not change much with temperature
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Graphene – Noise Amplitude
Noise Amplitude can also be calculated using fit for noise power at 1 Hz Lin, Avouris, Nano Lett., 2008, 8 (8), pp 2119–2125
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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
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Reduced Graphene Oxide
50 mm Resistance has a strong temperature dependence.
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Noise Power vs Temperature
Stronger temperature dependence of noise power. Sharp peaks occur at particular temperatures
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Assigning Noise Peaks Location of water freezing point vs. Temperature and Pressure Enhanced noise happens where we expect water to freeze in the vacuum chamber
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Noise Amplitude
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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
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Prof. A.T. Charlie Johnson
Johnson Group UPenn Prof. A.T. Charlie Johnson 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. Dr. Zhengtang Luo Dr. Brett Goldsmith Dr. Sasa Zaric Sam Khamis Bob Johnson Luke Somers Ye Lu Ryan Jones Matthew Berck Dan Singer Nicholas Kybert Thomas Ly Thanks to: IC Postdoc DARPA ARO
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