TY - JOUR
T1 - Limits of performance gain of aligned CNT over randomized network
T2 - Theoretical predictions and experimental validation
AU - Pimparkar, Ninad
AU - Kocabas, Coskun
AU - Kang, Seong Jun
AU - Rogers, John
AU - Alam, Muhammad Ashraful
N1 - Funding Information:
Manuscript received February 15, 2007; revised April 19, 2007. This work was supported in part by the Network of Computational Nanotechnology and in part by the Lilly Foundation. The review of this letter was arranged by Editor J. Sin.
PY - 2007/7
Y1 - 2007/7
N2 - Nanobundle thin-film transistors (NB-TFTs) that are based on random networks of single-walled carbon nanotubes are often regarded as high performance alternative to amorphous-Si technology for various macroelectronic applications involving sensors and displays. Here, we use stick-percolation model to study the effect of collective (stick) alignment on the performance of NB-TFTs. For long-channel TFT, small degree of alignment improves the drain current due to the reduction of average path length; however, near-parallel alignment degrades the current rapidly, reflecting the decrease in the number of connecting paths bridging the source/drain. In this paper, we 1) use a recently developed alignment technique to fabricate NB-TFT devices with multiple densities D, alignment θ, stick length LS, and channel length LC; 2) interpret the experimental data with a stick-percolation model to develop a comprehensive theory of NB-TFT for arbitrary D, θ, LS, and LC; and 3) demonstrate theoretically and experimentally the feasibility of fivefold enhancement in current gain with optimized transistor structure.
AB - Nanobundle thin-film transistors (NB-TFTs) that are based on random networks of single-walled carbon nanotubes are often regarded as high performance alternative to amorphous-Si technology for various macroelectronic applications involving sensors and displays. Here, we use stick-percolation model to study the effect of collective (stick) alignment on the performance of NB-TFTs. For long-channel TFT, small degree of alignment improves the drain current due to the reduction of average path length; however, near-parallel alignment degrades the current rapidly, reflecting the decrease in the number of connecting paths bridging the source/drain. In this paper, we 1) use a recently developed alignment technique to fabricate NB-TFT devices with multiple densities D, alignment θ, stick length LS, and channel length LC; 2) interpret the experimental data with a stick-percolation model to develop a comprehensive theory of NB-TFT for arbitrary D, θ, LS, and LC; and 3) demonstrate theoretically and experimentally the feasibility of fivefold enhancement in current gain with optimized transistor structure.
KW - Aligned carbon nanotube (CNT) networks
KW - Percolation threshold
KW - Random CNT networks
KW - Stick percolation
KW - Thin-film transistors (TFTs)
KW - Transistor models
UR - http://www.scopus.com/inward/record.url?scp=34447276692&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=34447276692&partnerID=8YFLogxK
U2 - 10.1109/LED.2007.898256
DO - 10.1109/LED.2007.898256
M3 - Article
AN - SCOPUS:34447276692
SN - 0741-3106
VL - 28
SP - 593
EP - 595
JO - IEEE Electron Device Letters
JF - IEEE Electron Device Letters
IS - 7
ER -