Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optimization of nonhomogeneous indium-gallium-nitride Schottky-barrier
  thin-film solar cells   A two-dimensional model was developed to simulate the optoelectronic
characteristics of indium-gallium-nitride (InGaN), thin-film, Schottky-barrier
solar cells. The solar cells comprise a window, designed to reduce the
reflection of incident light, Schottky-barrier and ohmic front electrodes, an
n-doped InGaN wafer, and a metallic periodically corrugated back-reflector
(PCBR). The ratio of indium to gallium in the wafer varies periodically
throughout the thickness of the absorbing layer of the solar cell. Thus, the
resulting InGaN wafer's optical and electrical properties are made to vary
periodically. This material nonhomogeneity could be physically achieved by
varying the fractional composition of indium and gallium during deposition.
Empirical models for indium nitride and gallium nitride were combined using
Vegard's law to determine the optical and electrical constitutive properties of
the alloy. The nonhomogeneity of the electrical properties of the InGaN aids in
the separation of the excited electron-hole pairs, while the periodicities of
optical properties and the back-reflector enable the incident light to couple
to multiple guided wave modes. The profile of the resulting
charge-carrier-generation rate when the solar cell is illuminated by the AM1.5G
spectrum was calculated using the rigorous coupled-wave approach. The
steady-state drift-diffusion equations were solved using COMSOL, which employs
finite-volume methods, to calculate the current density as a function of the
voltage. Mid-band Shockley-Read-Hall, Auger, and radiative recombination rates
were taken to be the dominant methods of recombination. The model was used to
study the effects of the solar-cell geometry and the shape of the periodic
material nonhomogeneity on efficiency. The solar-cell efficiency was optimized
using the differential evolution algorithm.

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The categories of this paper are: chem-ph
11
The categories of this paper are: hep-lat
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The categories of this paper are: q-alg
18
The categories of this paper are: econ
33
The categories of this paper are: plasm-ph
14
The categories of this paper are: math-ph
4
The categories of this paper are: cond-mat
2
The categories of this paper are: math
0
The categories of this paper are: hep-ph
1
The categories of this paper are: cs
25
The categories of this paper are: patt-sol
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
20
The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex
13
The categories of this paper are: quant-ph