Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Tuning bimetallic catalysts for a selective growth of SWCNTs   Recent advances in structural control during the synthesis of SWCNTs have in
common the use of bimetallic nanoparticles as catalysts, despite the fact that
their exact role is not fully understood. We therefore analyze the effect of
the catalyst' s chemical composition on the structure of the resulting SWCNTs
by comparing three bimetallic catalysts (FeRu, CoRu and NiRu). A specific
synthesis protocol is designed to impede the catalyst nanoparticle coalescence
mechanisms and stabilize their diameter distributions throughout the growth.
Owing to the ruthenium component which has a limited carbon solubility, tubes
grow in tangential mode and their diameter is close to that of their seeding
nanoparticle. By using as-synthesized SWCNTs as a channel material in field
effect transistors, we show how the chemical composition of the catalysts and
temperature can be used as parameters to tune the diameter distribution and
semiconducting-to-metallic ratio of SWCNT samples. Finally, a phenomenological
model, based on the dependence of the carbon solubility as a function of
catalyst nanoparticle size and nature of the alloying elements, is proposed to
interpret the results.

1
The categories of this paper are: cs
22
The categories of this paper are: chao-dyn
19
The categories of this paper are: eess
0
The categories of this paper are: hep-ph
14
The categories of this paper are: math-ph
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
13
The categories of this paper are: quant-ph
15
The categories of this paper are: nucl-ex
8
The categories of this paper are: hep-ex
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
17
The categories of this paper are: q-fin
26
The categories of this paper are: bayes-an
36
The categories of this paper are: cmp-lg
27
The categories of this paper are: comp-gas