Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Study of residual stress in reactively sputtered epitaxial Si-doped GaN
  films   Si-doped GaN films were grown on $\textit{c}$-sapphire by rf magnetron
reactive co-sputtering of GaAs and Si at various partial pressures of N$_2$ in
Ar-N2 growth atmosphere and their epitaxial character was ascertained by
phi-scans. Energy dispersive x-ray spectroscopy revealed $\thicksim$2 at.% Si
in all the films, but the N/Ga ratio decreased substantially as N$_2$
percentage was reduced from 100% to 10%. High resolution x-ray diffraction
revealed the dominant presence of edge dislocations ($\thicksim$10$^{12}$
cm$^{-2}$) in the films grown at 30% - 100% N$_2$, which decreased to
$\thicksim$5 x 10$^{11}$ cm$^{-2}$ at lower N$_2$ percentages, at which, the
density of screw dislocations was found to increase and attained values
comparable to that of edge dislocations. The lattice parameters ($\textit{a}$
and $\textit{c}$) were obtained independently to determine the in-plane and
out-of-plane components of strain in films, which were analyzed to deduce the
hydrostatic and biaxial strain contributions. The film grown at 100% N$_2$
displayed large micro-strain and hydrostatic strain due to excess/interstitial
nitrogen, both of which decreased with the initial reduction of N$_2$
percentage, but increased again below 30% N$_2$ due to Ar incorporation. The
films grown above 75% N$_2$ displayed compressive biaxial stress, which is
attributed to possible nitrogen incorporation into grain boundaries and tensile
side of edge dislocations. The reversal of biaxial stress to tensile character
in films grown below 75% N$_2$ is explained by the prevalence of in-plane
tensile stress generated during coalescence. The tensile stress decreased in
films grown below 30% N$_2$, which is ascribed to the Ar incorporation and
voided morphology. The presence of Si in the films does not have a significant
influence on strain behaviour and appears to be masked by the dominant
growth-related intrinsic effects.

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The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
9
The categories of this paper are: nlin
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
15
The categories of this paper are: nucl-ex
14
The categories of this paper are: math-ph
19
The categories of this paper are: eess
37
The categories of this paper are: supr-con
34
The categories of this paper are: chem-ph
2
The categories of this paper are: math
1
The categories of this paper are: cs
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys