posted on 2021-06-07, 16:07authored byXiaomei Yao, Shengxi Zhang, Qiang Sun, Peizong Chen, Xutao Zhang, Libo Zhang, Jian Zhang, Yan Wu, Jin Zou, Pingping Chen, Lin Wang
The
advent of topological semimetals with peculiar band structure
and exotic transport provides an unprecedented material platform that
allows exploring novel optoelectronics for circumventing technological
bottlenecks. Cd3As2, a three-dimensional Dirac
semimetal, represents a hallmark system for studying nontrivial quantum
phenomena led by Dirac/Weyl physics. However, controllable growth
and device implementation are still in their infancy due to lack of
efficient ways to make use of light-induced effects in semimetals.
In this study, highly sensitive, low-energy photodetection up to terahertz
(THz) band wavelength along with fast response at room temperature
has been implemented in an antenna-assisted Cd3As2 planar structure, which is derived from molecular-beam epitaxial
growth. It is demonstrated that the THz photodetector based on semimetal
Cd3As2 films possesses a responsivity of 0.04
A/W and a NEP value of 430 pW/Hz1/2. Nonequilibrium manipulation
of Dirac fermions with thickness-controlled gap phases and an electromagnetic-coupling
effect has been well exploited. Our results portray opportunities
for developing high-performance, scalable low-energy photodetectors
enabled by a Dirac semimetal, which is promising for broadband photoresponses
in the highly pursued THz band.