Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ambipolar tunneling in near-surface quantum wells   We study the photoluminescence from a near-surface quantum well in the regime
of ambipolar tunneling to the surface states. Under steady-state excitation an
electric field develops self-consistently due to the condition of equal
tunneling currents for electrons and holes. The field induces a Stark shift of
the photoluminescence signal which compares well with experimental data from
near-surface GaAs/AlGaAs single quantum wells.

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The categories of this paper are: alg-geom
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The categories of this paper are: funct-an
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The categories of this paper are: math
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The categories of this paper are: stat
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The categories of this paper are: econ
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The categories of this paper are: q-alg
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The categories of this paper are: plasm-ph
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The categories of this paper are: hep-th
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The categories of this paper are: acc-phys
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The categories of this paper are: math-ph
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The categories of this paper are: q-bio
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The categories of this paper are: hep-lat
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The categories of this paper are: solv-int
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The categories of this paper are: eess
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The categories of this paper are: gr-qc
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The categories of this paper are: hep-ex