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Schottky Diodes Using SWNT Networks Bryan Hicks Brigham Young University. Diodes and Transistors. An ever increasing number in an ever decreasing area. Why Carbon Nanotubes ?. Ballistic transport –Low power No chemical passivation necessary allows for a variety of different insulators
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Schottky Diodes Using SWNT NetworksBryan HicksBrigham Young University
Diodes and Transistors An ever increasing number in an ever decreasing area
Why Carbon Nanotubes? • Ballistic transport –Low power • No chemical passivation necessary allows for a variety of different insulators • Current densities of 109 A/cm2 vs. 103 A/cm2 for silicon • Large mobilities for high-speed devices • Can be semiconducting or metallic
Carbon Nanotube Networks • Random networks of tubes • No processing necessary • Low resistance at CNT junctions • 1/3 metallic, 2/3 semiconducting • Have properties of both metals and semiconductors
Fabrication Process • Deposit Au and Al electrodes on to a Si02/Si chip with SWNT networks • Wire bond the electrodes to a chip carrier
Current Rectification Properties Maximum Current Capacities: 8 μA & 22 μA On/off ratios: 20 & 5 Series Resistances:136 kΩ & 375 kΩ
Gate Voltage Characterization • Current decreases as carriers are removed • Current increases as carriers are introduced • The hysteresis seen is due to carrier trapping seen in other CNT transistors as well
Actual Devices • We suspect that the electrode spacing plays a critical role in achieving current rectification. • No rectification in device on left • Varying rectification in the two devices on the right
Summary • Carbon Nanotube Networks present an economic way to incorporate CNT properties into macroelectronics • Electrode spacing appears to affect mobility and current rectification
Sources • C. Lu, L. An, Q. Fu, J. Liua, H. Zhang and J. Murduck. Appl. Phys. Lett. 88, 133501 (2006) • P. Avouris, J. Appenzeller, Richard Martel, And S. J. Wind. Proceedings of the IEEE. 91, 11 (2003) Acknowledgements • Rocky Mountain Space Grant Consortium • Summer Internship • ESMD Faculty/Student mentor program • BYU College of Physical and Mathematical Sciences • Brigham Young University • David Allred, Jon Brame, Johnathan Goodsell • Goddard Space Flight Center Code 541 • Stephanie Getty, Rachel Bis, Dewey Dove