Covalent Polymeric Framework/ Bi 2Se 3-Based Heterostructure for Highly Efficient Wideband Photodetector

This article reports an organic/inorganic hybrid wideband photodetector (PD) made of a topological insulator (TI), Bi2Se3, and a donor-acceptor covalent polymeric framework (CPF) material (PDI-Tz) on a p-type Si substrate. Due to the formation of a strong type-II heterojunction between the CPF and TI, remarkably low dark current levels are expected. The fabricated PD exhibited a broadband photodetection capability ranging between 400 and 1100 nm with a peak responsivity and detectivity of 11.91 A/W and
$2.51\times 10{^{{15}}}$
Jones at 400 nm. In addition, the PD offered an ultrahigh external quantum efficiency (EQE) of 3457% at 400 nm. Furthermore, stable time-dependent photoresponse characteristics with millisecond-order transient metrics indicate the efficacy of the fabricated PD.