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 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 from the power spectrum of the current. (using FFT) b = 1 for most devices

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.

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 Noise Amplitude can also be calculated using fit for noise power at 1 Hz Lin, Avouris, Nano Lett., 2008, 8 (8), pp 2119–2125

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 50 mm Resistance has a strong temperature dependence.

Noise Power vs Temperature Stronger temperature dependence of noise power. Sharp peaks occur at particular temperatures

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

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

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