Polarization-sensitive, self-powered photodetector based on a SnO₂/MoS₂ van der Waals heterojunction

Polarization-sensitive ultraviolet photodetectors have a wide range of applications in remote sensing, analytical imaging, information encryption, and anti-counterfeiting. Herein, one-dimensional tin dioxide (SnO₂) single crystals by using the chemical vapor deposition (CVD) method are reported. The high in-plane anisotropic structure, phonon vibrations, and refractive index of the SnO₂ crystals are experimentally elucidated. Based on CVD-grown SnO₂ single crystals, a mixed-dimensional SnO₂/MoS₂ van der Waals (vdWs) heterostructure is proposed to realize a polarization-sensitive self-powered ultraviolet photodetector. Owing to the high-quality vdWs heterojunction, the device exhibits pronounced photovoltaic performances. Significantly, the anisotropy ratio of SnO₂/MoS₂ devices can be as high as 4.2 compared to 1.7 for pure SnO₂ devices. The high-resolution polarization imaging capability of the vdWs device was further demonstrated. Moreover, the polarized image maintains an anisotropy ratio of about 4.0 and has an excellent stability under long-term operating conditions without degradation. Our work provides a strategy for fabricating a low-dimensional SnO₂-based vdWs heterostructure for high-performance polarization-sensitive ultraviolet detection.