Near-infrared (NIR) polarization photodetectors with
two-dimensional
(2D) semiconductors and their van der Waals (vdW) heterostructures
have presented great impact for the development of a wide range of
technologies, such as in the optoelectronics and communication fields.
Nevertheless, the lack of a photogenerated charge carrier at the device’s
interface leads to a poor charge carrier collection efficiency and
a low linear dichroism ratio, hindering the achievement of high-performance
optoelectronic devices with multifunctionalities. Herein, we present
a type-II violet phosphorus (VP)/InSe vdW heterostructure that is
predicted via density functional theory calculation and confirmed
by Kelvin probe force microscopy. Benefiting from the type-II band
alignment, the VP/InSe vdW heterostructure-based photodetector achieves
excellent photodetection performance such as a responsivity (R) of 182.8 A/W, a detectivity (D*) of
7.86 × 1012 Jones, and an external quantum efficiency
(EQE) of 11,939% under a 1064 nm photon excitation. Furthermore, the
photodetection performance can be enhanced by manipulating the device
geometry by inserting a few layers of graphene between the VP and
InSe (VP/Gr/InSe). Remarkably, the VP/Gr/InSe vdW heterostructure
shows a competitive polarization sensitivity of 2.59 at 1064 nm and
can be integrated as an image sensor. This work demonstrates that
VP/InSe and VP/Gr/InSe vdW heterostructures will be effective for
promising integrated NIR optoelectronics.