Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Black Phosphorus Mid-Infrared Photodetectors with High Gain   Recently, black phosphorus (BP) has joined the two dimensional material
family as a promising candidate for photonic applications, due to its moderate
bandgap, high carrier mobility, and compatibility with a diverse range of
substrates. Photodetectors are probably the most explored BP photonic devices,
however, their unique potential compared with other layered materials in the
mid-infrared wavelength range has not been revealed. Here, we demonstrate BP
mid infrared detectors at 3.39 um with high internal gain, resulting in an
external responsivity of 82 A/W. Noise measurements show that such BP
photodetectors are capable of sensing low intensity mid-infrared light in the
picowatt range. Moreover, the high photoresponse remains effective at kilohertz
modulation frequencies, because of the fast carrier dynamics arising from BPs
moderate bandgap. The high photoresponse at mid infrared wavelengths and the
large dynamic bandwidth, together with its unique polarization dependent
response induced by low crystalline symmetry, can be coalesced to promise
photonic applications such as chip-scale mid-infrared sensing and imaging at
low light levels.

29
The categories of this paper are: funct-an
13
The categories of this paper are: quant-ph
20
The categories of this paper are: acc-phys
31
The categories of this paper are: ao-sci
16
The categories of this paper are: stat
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
6
The categories of this paper are: astro-ph
18
The categories of this paper are: econ
21
The categories of this paper are: adap-org
27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
1
The categories of this paper are: cs
5
The categories of this paper are: gr-qc