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Proceedings Paper

Metal-semiconductor-metal (MSM) photodetectors based on single-walled carbon nanotube film-silicon Schottky contacts
Author(s): Ashkan Behnam; Jason L. Johnson; Yongho Choi; M. Günhan Ertosun; Zhuangchun Wu; Andrew G. Rinzler; Pawan Kapur; Krishna C. Saraswat; Ant Ural
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Paper Abstract

We fabricate and experimentally characterize metal-semiconductor-metal (MSM) photodetectors with CNT film Schottky electrodes on n-type and p-type silicon substrates. We extract a Schottky barrier height of ~0.45 eV and ~0.51 eV for CNT films on n-type and p-type Si respectively. The extracted barrier height corresponds to a CNT film workfunction of 4.5-4.7 eV, which is within the range of the previously reported workfunction values for individual CNTs. Furthermore, we find that while at temperatures above 240°K thermionic emission is the dominant transport mechanism, at lower temperatures tunneling begins to dominate. We also characterize the photoresponse of the CNT film-Si MSM photodetector by illuminating the samples with a 633 nm HeNe laser. We observe that while the photocurrent of the CNT film MSM devices is similar to that of the Ti/Au control samples at high biases, their lower dark current results in a higher photo-to-dark current ratio relative to the control devices. We explain these observations by comparing the two interfaces. This work opens up the possibility of integrating CNT films as transparent and conductive Schottky electrodes in conventional semiconductor electronic and optoelectronic devices.

Paper Details

Date Published: 20 February 2008
PDF: 8 pages
Proc. SPIE 6885, MEMS/MOEMS Components and Their Applications V. Special Focus Topics: Transducers at the Micro-Nano Interface, 68850A (20 February 2008); doi: 10.1117/12.761935
Show Author Affiliations
Ashkan Behnam, Univ. of Florida (United States)
Jason L. Johnson, Univ. of Florida (United States)
Yongho Choi, Univ. of Florida (United States)
M. Günhan Ertosun, Stanford Univ. (United States)
Zhuangchun Wu, Univ. of Florida (United States)
Andrew G. Rinzler, Univ. of Florida (United States)
Pawan Kapur, Stanford Univ. (United States)
Krishna C. Saraswat, Stanford Univ. (United States)
Ant Ural, Univ. of Florida (United States)

Published in SPIE Proceedings Vol. 6885:
MEMS/MOEMS Components and Their Applications V. Special Focus Topics: Transducers at the Micro-Nano Interface
Srinivas A. Tadigadapa; Babak A. Parviz; Albert K. Henning, Editor(s)

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