α-In₂Se₃ Nanoflakes Modulated by Ferroelectric Polarization and Pt Nanodots for Photodetection

α-In2Se3 is an interesting two-dimensional (2D) van der Waal s(vdW) ferroelectric material with simultaneous intercorrelated in-plane and out-of-plane polarization, and its bandgap is only about 1.3–1.4 eV, enabling the possibility of ultralow-power nanophotodetectors. However, few researchers focus on the relationship between the ferroelectric polarization and photoresponsivity for α-In2Se3 based photodetectors, and finding ways to improve the on/off current ratio. In this report, α-In2Se3 nanoflakes based planar devices were fabricated. We have demonstrated that the ferroelectric polarization has a great influence on the response time and on/off current ratio, and discovered that the Pt nanodots sputtered on the α-In2Se3 surface could enhance the on/off current ratio to 2 × 109%. The performance of α-In2Se3 based planar device is very competitive comparing with the similar nanophotodetectors. All these may provide an effective way to improve the performance of nanophotodetectors, and highlight the potential of 2D vdW materials for novel nanophotodetectors.