Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Single Crystalline InGaAs Nanopillar Grown on Polysilicon with
  Dimensions beyond Substrate Grain Size Limit   Monolithic integration of III-V optoelectronic devices with materials for
various functionalities inexpensively is always desirable. Polysilicon
(poly-Si) is an ideal platform because it is dopable and semi-conducting and
can be deposited and patterned easily on a wide range of low cost substrates.
However, the lack of crystalline coherency in poly-Si poses an immense
challenge for high-quality epitaxial growth. In this work, we demonstrate, for
the first time, direct growth of micron-sized InGaAs/GaAs nanopillars on
polysilicon. Transmission electron microscopy shows that the micron-sized
pillars are single-crystalline and single Wurzite-phase, far exceeding the
substrate crystal grain size ~100nm. The high quality growth is enabled by the
unique tapering geometry at the base of the nanostructure, which reduces the
effective InGaAs/Si contact area to < 40 nm in diameter. The small footprint
not only reduces stress due to lattice mismatch but also prevents the
nanopillar from nucleating on multiple Si crystal grains. This relaxes the
grain size requirement for poly-Si, potentially reducing the cost for poly-Si
deposition. Lasing is achieved in the as-grown pillars under optical pumping,
attesting their excellent crystalline and optical quality. These promising
results open up a pathway for low-cost synergy of optoelectronics with other
technologies such as CMOS integrated circuits, sensing, nanofluidics, thin film
transistor display, photovoltaics, etc.

21
The categories of this paper are: adap-org
31
The categories of this paper are: ao-sci
1
The categories of this paper are: cs
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph
34
The categories of this paper are: chem-ph
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
19
The categories of this paper are: eess
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin