Ferroelectrically Enhanced Polarization-Sensitive AuNPs-Deposited α-In₂Se₃/PdSe₂ Photodetector with Ultrahigh Photoresponsivity and Detectivity

To enhance the detectivity and overall performance of the device, this study presents a polarization-sensitive photodetector by leveraging the anisotropic in-plane crystal structures of α-In₂Se₃ and PdSe₂. By incorporation of Au nanoparticles (AuNPs) and exploiting the ferroelectrically controllable polarization of α-In₂Se₃, the proposed photodetector achieves exceptional polarization detection capabilities. Specifically, aligning the poling direction of α-In₂Se₃ with the <i>a</i>-axis of PdSe₂ and the incorporation of AuNPs yield a remarkable photoresponsivity of 4137 A/W and a detectivity of 1.158 × 10¹³ Jones at a near-infrared wavelength of 980 nm, along with a rapid response time of 29 μs. Polarization sensitivity of the device was significantly enhanced by a factor of 5.9, from 2.56 to 15.1, through the poling of the two-dimensional ferroelectric α-In₂Se₃. These findings represent a substantial advancement in the development of high-performance, polarization-sensitive photodetectors using atomically thin 2D materials, offering new opportunities for next-generation optoelectronic applications.