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Proceedings Paper

A computational study of carbon nanotube optoelectronic devices
Author(s): Youngki Yoon; Yijian Ouyang; Muhammad A. Alam; Jing Guo
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Paper Abstract

Since the first demonstration of electroluminescence (EL) from a CNTFET about three year ago, significant progress has been achieved in CNT optoelectronics. We have developed semiclassical and quantum transport simulators for CNT optoelectronic devices. A self-consistent simulation, which couples a quantum treatment of the metal-CNT contacts to a semiclassical treatment of the channel, is performed to understand carrier transport and light emission in a CNT infrared emitter. The results show that when the channel is long, light emission significantly affects carrier transport, and reduces the source-drain current by a factor of 2 in ambipolar transport regime. The experimentally observed light-spot movement along the channel can be mostly understood and explained by a simple, semiclassical picture. The photoconductivity of carbon nanotube (CNT) Schottky barrier transistors is studied by solving the nonequilibrium Green's function transport equation. The model provides a detailed and coherent picture of electron-photon coupling and quantum transport effects. The photocurrent shows peaks at photon energies near the subband gaps, which can be engineered by controlling the CNT diameter. Electron-phonon coupling (i) slightly broadens the peaks, (ii) leads to phonon-assisted photocurrent at certain energy ranges, and (iii) changes the energy-resolved photocurrent. We also show that the metal/CNT barrier height has a much smaller effect on the photocurrent than on the dark current. We also show the important role of sub-bandgap impact ionization and excitation in CNT devices.

Paper Details

Date Published: 19 October 2006
PDF: 12 pages
Proc. SPIE 6370, Nanomaterial Synthesis and Integration for Sensors, Electronics, Photonics, and Electro-Optics, 63700G (19 October 2006); doi: 10.1117/12.690714
Show Author Affiliations
Youngki Yoon, Univ. of Florida (United States)
Yijian Ouyang, Univ. of Florida (United States)
Muhammad A. Alam, Purdue Univ. (United States)
Jing Guo, Univ. of Florida (United States)

Published in SPIE Proceedings Vol. 6370:
Nanomaterial Synthesis and Integration for Sensors, Electronics, Photonics, and Electro-Optics
Nibir K. Dhar; Achyut K. Dutta; M. Saif Islam, Editor(s)

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