Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Synthesis of quantum-confined CdS nanotubes   CdS nanotubes with wall thickness comparable to excitonic diameter of the
bulk material are synthesized by a chemical route. A change in experimental
conditions result in formation of nanowires, and well-separated nanoparticles.
The diameter and wall thickness of nanotubes measured to be 14.4 $\pm$ 6.1 and
4.7 $\pm$ 2.2 nm, respectively. A large number of CdS nanocrystallites having
wurzite structure constitute these nanotubes. These nanotubes show high energy
shifting of optical absorption and photoluminescence peak positions, compared
to its bulk value, due to quantum confinement effect. It is proposed that
nucleation and growth of bubbles and particles in the chemical reaction, and
their kinetics and interactions are responsible for the formation of nanotubes.

29
The categories of this paper are: funct-an
21
The categories of this paper are: adap-org
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
13
The categories of this paper are: quant-ph
2
The categories of this paper are: math
34
The categories of this paper are: chem-ph
36
The categories of this paper are: cmp-lg
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
3
The categories of this paper are: physics
28
The categories of this paper are: alg-geom
31
The categories of this paper are: ao-sci
19
The categories of this paper are: eess
12
The categories of this paper are: nucl-th