Highly Efficient, Ultrabroad PdSe<sub>2</sub> Phototransistors from Visible to Terahertz Driven by Mutiphysical Mechanism
Zhuo Dong, Wenzhi Yu, Libo Zhang, Haoran Mu, Liu Xie, Jie Li, Yan Zhang, Luyi Huang, Xiaoyue He, Lin Wang, Shenghuang Lin, Kai Zhang
Abstract
The noble transition metal dichalcogenide palladium diselenide (PdSe2) is an ideal candidate material for broad-spectrum photodetection owing to the large bandgap tunability, high mobility, low thermal conductivity, and large Seebeck coefficient. In this study, self-powered ultrabroadband PdSe2 photodetectors from the visible–infrared to terahertz (THz) region driven by a mutiphysical mechanism are reported. In the visible–infrared region, the photogenerated electron–hole pairs in the PdSe2 body are quickly separated by the built-in electric field at the metal–semiconductor interface and achieve a photoresponsivity of 28 A·W–1 at 405 nm and 0.4 A·W–1 at 1850 nm. In the THz region, PdSe2 photodetectors display a room-temperature responsivity of 20 mA·W–1 at 0.10 THz and 5 mA·W–1 at 0.24 THz based on efficient production of hot carriers in an antenna-assisted structure. Owing to the fast response speed of ∼7.5 μs and low noise equivalent power of ∼900 pW·Hz–1/2, high-resolution transmission THz imaging is demonstrated under an ambient environment at room temperature. Our research validates the great potential of PdSe2 for broadband photodetection and provides a possibility for future optoelectronic applications.