Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Voltage controlled terahertz transmission through GaN quantum wells   We report measurements of radiation transmission in the 0.220--0.325 THz
frequency domain through GaN quantum wells grown on sapphire substrates at room
and low temperatures. A significant enhancement of the transmitted beam
intensity with the applied voltage on the devices under test is found. For a
deeper understanding of the physical phenomena involved, these results are
compared with a phenomenological theory of light transmission under electric
bias relating the transmission enhancement to changes in the differential
mobility of the two-dimensional electron gas.

19
The categories of this paper are: eess
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The categories of this paper are: adap-org
25
The categories of this paper are: patt-sol
27
The categories of this paper are: comp-gas
34
The categories of this paper are: chem-ph
7
The categories of this paper are: hep-th
29
The categories of this paper are: funct-an
23
The categories of this paper are: solv-int
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The categories of this paper are: q-alg
31
The categories of this paper are: ao-sci
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The categories of this paper are: q-fin
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The categories of this paper are: hep-lat
24
The categories of this paper are: dg-ga
5
The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph