Correlation of Electrical Conductivity and Temperature of Carbon Nanotubes

PROBLEM

This experimental investigation will establish a relationship between the conductivity of pure, single layer carbon nanotubes and temperature.


SUBPROBLEMS

This research will examine literature that gives known correlations between electrical properties of carbon nanotubes and temperature. This research team will collect new data that will be combined with previous. Collected data will be used to generate equations that relate conductivity of nanotubes to temperature.


IMPORTANCE OF THE STUDY

The research has various applications in the field of nanoscopic circuitry(1). Use of nanotube circuitry in various technological applications, especially those relating to outer space, requires that nanotubes function over the entire MILSPEC temperature range(1,2). It is therefore important to determine the functionality of nanotube circuitry in different conditions.


REVIEW OF THE RELATED LITERATURE

ROTMAN, DAVID
Nanotubes have application in computing technology. A 1 square cm chip of nanotube-based computer memory would be able to store 125 gigabytes of nonvolatile memory. Nanotube-based memory has access speeds similar to that of RAM but are without a power requirement to keep it operational. With such advantages, nanotube-based circuitry could potentially solve problems inherent in the design of faster computers.

LEUTWYLER, KRISTIN
Researchers have discovered a way to make precise nanotubes en masse in a parallel lattice. Nanotubes were created in a mold to specifications of the researchers. The researchers then created optimum nanotubes for wires that are long, thin, operating in parallel, and with excellent electrical and heat conductivity.

ELECTRICAL CONDUCTIVITY OF METAL
Data is given for the conductivity, tensile strength, and resistance coefficients of metals at 20 degrees Celsius. Equations relating tensile strength and temperature are also given.

TEMPERATURE DEPENDENT THERMAL CONDUCTIVITY OF UNDOPED POLYCRYSALLINE SILICON LAYERS
Rresearchers have empirically derived an equation relating temperature and conductivity in Polycrystalline silicon, a material used in microelectronic and micro-electromechanical devices. This research measures the in-plane thermal conductivities of free-standing undoped polycrystalline layers between 20 and 300 K.

METHODS AND MATERIALS

To test the conductivity of the pure, single layered carbon nanotubes as a function of temperature, a modified environmental chamber is used to house the experiment. This modified environmental chamber will consist of a chamber of the type described by Dr. Steven Tidrow(2) altered to include an atomic force microscope equipped with a conducting probe tip (1). The environmental chamber will be used to cycle through a variety of temperature conditions. Measurements will be taken using the conducting probe tip of the atomic force microscope.

The atomic force microscope will allow the manipulation of nanotubes within the environmental chamber and conductivity measurements to be taken of the samples. A sample of carbon nanotubes will be prepared and connected to Au electrical contacts using standard lithographic techniques(1). With these techniques, one end of a nanotube is contacted to the Au while the other end is left free to be contacted by the conducting tip of the atomic force microscope. Once a connection with the microscope is achieved, the conductivity of the nanotube sample may be measured.

DATA, TREATMENT AND INTERPRETATION

DATA



Temperature of Sample (Degrees Kelvin)Conductivity of Sample (Mhos)
   


TREATMENT

The independent variable of the experiment is temperature, in degrees Celsius. The dependent variable is conductivity of the nanotubes, measured in mhos. The data will be collected and graphed as degrees Celsius versus mhos to determine a relationship between temperature and conductivity. After analysis, an appropriate statistical regression will be applied to the data so that a mathematical model of the properties of the carbon nanotubes can be generated.


INTERPRETATION

It is expected that the data will demonstrate an inverse relationship between conductivity and temperature.


QUALIFICATIONS OF THE RESEARCHERS

BARON, MATT

Matt is the editor. He is knowledgeable in physical and analytical chemistry and nanotechnology. His literature searches have produced much of the information on which the experimental design is based.

GLASSER, DAVIS

Davis is the team leader. He brings to the team his experience from the Blair Robot Project and multiple engineering projects at school.

MCILWAIN, BEN

Ben is a technology-oriented group member who brings computer knowledge and programming abilities to the research group. He is also knowledgeable in basic chemistry and atomic interactions. His knowledge of nanotechnology aids the group in experimental design.

PACKMAN, JOSHUA

Joshua is the experimental design specialist for the group. Josh brings experience from several engineering projects at school as well from SEAP.



PROCESS, TIMETABLE

I. Gather materials 30 Days
II. Construct testing device 45 Days
III. Conduct tests 180 Days
IV. Analyze data 60 Days
V. Write first draft of report 15 Days
VI. Revise report 25 Days
VII. Present findings 2 Days
REFERENCES AND NOTES


1. Dai, H., Wong, E. W., Lieber, C. M., (1996). Probing Electrical Tansport in Nanomaterials: Conductivity of Individual Carbon Nanotubes. Science, 272, 5261. Retrieved March 7, 2002, from http://proquest.umi.com/pdqweb?Did=000000009686927&Fmt=3&Deli=1&Mtd=1&Idx=3&Sid=1&RQT=309

2. Tidrow, S. C., Potrepka, D. M., Tauber, A., et al. Microwave Measurements of Dielectric Constant and Loss Tangent of Microwave Materials as Functions of Temperature and Frequency. (n.d.). Retrieved March 7, 2002, from http://www2.ijs.si/~mma2000/ABSTRACTS.HTML#Tidrow


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