Two-dimensional (2D) layered materials with low crystal symmetries have exhibited unique anisotropic physical properties. Here, we report systematic studies on the photoresponse of field effect transistors (FETs) fabricated using quasi-one-dimensional ZrS3 nanoflakes. The as-fabricated phototransistors exhibit a broadband photocurrent response from ultraviolet to visible regions, where the responsivity and detectivity can be enhanced via additional gate voltages. Furthermore, benefiting from the strong in-plane anisotropy of ZrS3, we observe a gate-voltage and illumination wavelength-dependent polarized photocurrent response, while its sub-millisecond-time response speed is also polarization-dependent. Our results demonstrate the flexible tunability of photodetectors based on anisotropic layered semiconductors, which substantially broadens the application of low symmetry layered materials in polarization-sensitive optoelectronic devices.

Abstract2D layered materials with low crystal symmetries exhibit unique anisotropic physical properties. Here the systematic studies on the optical modulation effects of such anisotropic 2D materials to isotropic 2D materials in their stacked van der Waals (vdW) heterostructures are reported. By applying angle‐resolved polarization spectroscopic characterizations on the MoS2/ZrS3 vdW heterostructure, periodic intensity variations of the Raman scattering and photoluminescence (PL) emission modes of monolayer MoS2 are observed, which are closely correlated to the anisotropic optical properties of the underlying ZrS3 layers. Such anisotropic optical modulation effects can be identified with the thickness of ZrS3 reduced to few layers (≈6 nm), and are attributed to the strong birefringence and dichroism effects in ZrS3 that cause reflection difference between its crystal axis, thus modulating the Raman/PL intensities of MoS2 via Fabry–Pérot interference effect. Furthermore, the polarized photocurrent response of the heterostructure is also demonstrated, where its major contribution originates from MoS2. This work develops a new methodology to tune the light–matter interactions and properties of isotropic 2D materials by the combination with anisotropic 2D materials, which substantially broadens the application of low symmetry layered materials in polarization sensitive optoelectronic devices.