Ferroelectrically Enhanced Polarization-Sensitive AuNPs-Deposited α-In<sub>2</sub>Se<sub>3</sub>/PdSe<sub>2</sub> Photodetector with Ultrahigh Photoresponsivity and Detectivity.

Jin, Hyeok Jun; Park, Cheolmin; Lee, Khang June; Kang, Mingu; Choi, Sung-Yool · Nano Lett · 2025

basic_science · Level V

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Abstract

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-In<sub>2</sub>Se<sub>3</sub> and PdSe<sub>2</sub>. By incorporation of Au nanoparticles (AuNPs) and exploiting the ferroelectrically controllable polarization of α-In<sub>2</sub>Se<sub>3</sub>, the proposed photodetector achieves exceptional polarization detection capabilities. Specifically, aligning the poling direction of α-In<sub>2</sub>Se<sub>3</sub> with the <i>a</i>-axis of PdSe<sub>2</sub> and the incorporation of AuNPs yield a remarkable photoresponsivity of 4137 A/W and a detectivity of 1.158 × 10<sup>13</sup> 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-In<sub>2</sub>Se<sub>3</sub>. 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.