Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electromagnetic approach to ultrathin solar cell efficiencies   Current methods for evaluating solar cell efficiencies cannot be applied to
extremely thin cells where phenomena from the realm of near field optics
prevail. We overcome this problem by offering a rigorous electromagnetic
calculation of solar cell efficiencies based on the fluctuation dissipation
theorem. Our approach is demonstrated by calculating the efficiency of a GaAs
solar cell with an Au back reflector for thicknesses well below the typical
wavelength of the solar flux. It is shown that near field optics affect the
performance of low dimensional solar cells.

10
The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga
6
The categories of this paper are: astro-ph
3
The categories of this paper are: physics
25
The categories of this paper are: patt-sol
32
The categories of this paper are: atom-ph
8
The categories of this paper are: hep-ex
12
The categories of this paper are: nucl-th
33
The categories of this paper are: plasm-ph
2
The categories of this paper are: math
11
The categories of this paper are: hep-lat
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg
18
The categories of this paper are: econ