Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Light emission from silicon with tin-containing nanocrystals   Tin-containing nanocrystals, embedded in silicon, have been fabricated by
growing an epitaxial layer of Si_{1-x-y}Sn_{x}C_{y}, where x = 1.6 % and y =
0.04 %, followed by annealing at various temperatures ranging from 650 to 900
degrees C. The nanocrystal density and average diameters are determined by
scanning transmission-electron microscopy to ~ 10^{17} cm^{-3} and ~ 5 nm,
respectively. Photoluminescence spectroscopy demonstrates that the light
emission is very pronounced for samples annealed at 725 degrees C, and
Rutherford back-scattering spectrometry shows that the nanocrystals are
predominantly in the diamond-structured phase at this particular annealing
temperature. The origin of the light emission is discussed.

12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
3
The categories of this paper are: physics
17
The categories of this paper are: q-fin
37
The categories of this paper are: supr-con
9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol
5
The categories of this paper are: gr-qc
19
The categories of this paper are: eess
23
The categories of this paper are: solv-int