Multilayer WSe₂/ZnO heterojunctions for self-powered, broadband, and high-speed photodetectors

Abstract

Self-powered broadband photodetectors have attracted great interest due to their applications in biomedical imaging, integrated circuits, wireless communication systems, and optical switches. Recently, significant research is being carried out to develop high-performance self-powered photodetectors (SPPDs) based on thin 2D materials and their heterostructures due to their unique optoelectronic properties. Herein, a vertical heterostructure based on p-type 2D WSe2 and n-type thin film ZnO is realized for photodetectors with a broadband response in the wavelength range of 300-850 nm. Due to the formation of a built-in electric field at the WSe2/ZnO interface and the photovoltaic effect, this structure exhibits a rectifying behaviour with a maximum photoresponsivity and detectivity of ⁓131 mA/W and ⁓3.92×1010 Jones, respectively, under an incident light wavelength of λ= 300 nm at zero voltage bias. It also shows a 3-dB cut-off frequency of ⁓300 Hz along with a fast response time of ⁓496 μs, making it suitable for high-speed self-powered optoelectronic applications. Furthermore, the facilitation of charge collection under reverse voltage bias results in a photoresponsivity as high as ⁓7160 mA/W and a large detectivity of ⁓1.18×1011 Jones at a bias voltage of -5 V. Hence, the p-WSe2/n-ZnO heterojunction is proposed as an excellent candidate for high-performance, self-powered, and broadband photodetectors.

Self-Powered ZnO@PdTe2/Si Heterojunction Photodetector with an Ultrafast Response for Color Imaging and Optical Communication

“…The main performance data of PdTe 2 and ZnO-based photodetectors are listed in Figure e and Table S1. Compared to the PdTe 2 -based device, our device has a 10–10 6 higher response time and an extended detection range to UV. ,, Compared to the ZnO/TMDC heterojunction device, the ZnO@PdTe 2 /Si heterojunction has a wider response range (254 nm–1.55 μm), and the D * and response/recovery times are improved by 10–10 3 . − …”

“…PdTe 2 and ZnO lattice spacings are 0.20 and 0.28 nm, respectively, with PdTe 2 being dominantly oriented (001). Figure S3a,b,d,e shows the results of X-ray photoelectron spectroscopy (XPS), in which peaks at about 336.25, 341.49, 575.54, 585.94, 532.81, 1022.98, and 1046.09 eV are attributed to the Pd 3d 5/2 , Pd 3d 3/2 , Te 3d 5/2 , Te 3d 3/2 , O 1s, Zn 2p 3/2 , and Zn 2p 1/2 orbitals, respectively. , In addition, the X-ray diffraction (XRD) patterns of PdTe 2 and ZnO show significant diffraction peaks (Figure S3c,f).…”

A visible-light photodetector based on heterojunctions between CuO nanoparticles and ZnO nanorods

“…Responsivity values of 0.03 and 0.01 mA·W −1 are obtained for 532 and 640 nm, respectively ( Figure 6b ). Since detectivity and photoconductive gain depend on the responsivity [ 52 ], the values of G and D are 0.69 × 10 −4 and 17.1 × 10 6 Jones for λ = 532 nm, and 0.19 × 10 −4 and 5.34 × 10 6 Jones for λ = 640 nm, which corresponds to the relatively low responsivity values at these wavelengths. Thereby, it can be concluded that the operation range of the CuO NPs/ZnO NRs photodetector could be extended to the visible region.…”

Integrating 2D layered materials with 3D bulk materials as van der Waals heterostructures for photodetections: Current status and perspectives

“…In recent years, TMDC/ZnO heterostructures have been focused on self‐powered and broadband detection 177–179 . In a recent study, a n‐MoS 2 /n‐ZnO heterojunction with type II band alignment was developed by depositing MoS 2 film onto ZnO film 180 .…”