Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Imaging charge and spin diffusion of minority carriers in GaAs   Room temperature electronic diffusion is studied in 3 mum thick epitaxial p+
GaAs lift-off films using a novel circularly polarized photoluminescence
microscope. The method is equivalent to using a standard optical microscope and
provides a contactless means to measure charge (L) and spin (L_s) diffusion
lengths. The measured values of L and L_s are in excellent agreement with the
spatially averaged polarization and a sharp reduction in these two quantities
(L from 21.3 mum to 1.2 mum and L_s from 1.3 mum to 0.8 mum) is measured with
increasing surface recombination. Outwards diffusion results in a factor of 10
increase in the polarization at the excitation spot.

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The categories of this paper are: atom-ph
9
The categories of this paper are: nlin
23
The categories of this paper are: solv-int
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The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
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The categories of this paper are: chem-ph
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The categories of this paper are: supr-con
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The categories of this paper are: stat
2
The categories of this paper are: math
14
The categories of this paper are: math-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: acc-phys
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-th
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The categories of this paper are: bayes-an
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The categories of this paper are: q-alg