Self‐Driven WSe₂/Bi₂O₂Se Van der Waals Heterostructure Photodetectors with High Light On/Off Ratio and Fast Response

Abstract

Benefiting from the superior electron mobility and good air‐stability, the emerging layered bismuth oxyselenide (Bi2O2Se) nanosheet has received considerable attention with the promising prospects for electronics and optoelectronics applications. However, the high charge carrier concentration and bolometric effect of Bi2O2Se give rise to the high dark current and relatively slow photoresponse, which severely impede further improvement of the performance of Bi2O2Se based photodetectors. Here, a WSe2/Bi2O2Se Van der Waals p‐n heterostructure is reported with a pronounced rectification ratio of 105 and a low reverse dark current of 10−11 A, as well as an enhanced light on/off ratio up to 618 under 532 nm light illumination. The device also exhibits a fast response speed of 2.6 µs and a broadband detection capability from 365 to 2000 nm due to the efficient charge separation and strong interlayer coupling at the interface of the two flakes. Importantly, the built‐in potential in the WSe2/Bi2O2Se heterostructure offers a competitive self‐powered photodetector with the light on/off ratio above 105 and a photovoltaic responsivity of 284 mA W−1. The WSe2/Bi2O2Se heterostructure shows promising potentials for high‐performance self‐driven photodetector applications.

Ultrathin 2D ternary Bi2Te2Se flakes for fast-response photodetectors with gate-tunable responsivity

“…The extracted power-dependent photocurrent (I ph ) is plotted in Fig. 4g and fitted with formula [51]:…”

“…And the trapping sites may come from the impurities at the interface between BTS flakes and substrate, or the charge impurity states inside the transported flakes [46,52]. What is more, we calculated the responsivity (R) of the BTS photodetector according to the formula [51]: R = I ph /PS, where S is the effective channel area estimated to be 44 μm 2 as shown in Fig. S3.…”

Strong Interlayer Transition in Few‐Layer InSe/PdSe2 van der Waals Heterostructure for Near‐Infrared Photodetection

“…[15] WSe 2 /Bi 2 Te 3 heterostructure has capability to get the R of 27 mA W −1 at 1550 nm wavelength as reported by H. Liu et al [16] P. Luo et al demonstrated the vdWs heterostructure comprising from WSe 2 /Bi 2 O 2 Se. They observed that fabricated device has detection ability in NIR regime up to 2000 nm but suffers from low detectivity (D*) and R. [17] Recently, PdSe 2 /WS 2 vdWs heterostructure demonstrated by J. C. Ho group exhibits broadband photoresponse from visible (532 nm) to NIR spectrum (1550 nm) but has low R, that is, 3.19 and 0.019 mA W −1 at visible (635 nm) and NIR (1550 nm) spectrum, respectively. [18] Interlayer coupling has a significant influence on the electronic/ optic performance of vdWs heterojunction devices, and strong interlayer coupling in 2D vdWs heterojunction is always desirable for efficient charge transfer and high-speed response.…”

Mechanism, Material, Design, and Implementation Principle of Two-Dimensional Material Photodetectors

“…While conventional heterojunction photodetectors show great advantages, they have difficulty covering a broad spectrum in terms of spectral response due to bandgap limitations [139][140][141][142]. Huang et al developed a PtTe 2 /graphene heterostructured photodetector (Figure 9d) [102].…”