Large-area and low-temperature synthesis of few-layered WS ₂ films for photodetectors

Abstract

WS2-based photodetectors were fabricated by sputtering and electron beam irradiation (EBI), and the effect of EBI on the crystallization of WS2 films was investigated. EBI at 1 kV energy for 1 min transformed the as-deposited amorphous structure of WS2 film into a two-dimensional (2D) layered crystalline structure with high uniformity over a 50.8 mm diameter wafer. Additionally, EBI enhanced the photoelectrical properties of WS2-based photodetectors. The as-deposited WS2 film yielded a responsivity of 0.10 mA · W−1 under 450 nm laser irradiation, but showed no response under 532 and 635 nm laser wavelengths. However, after 1 kV and 3 kV EBI of the WS2 films, the responsivities under laser irradiation at 450, 532, and 635 nm were 0.36, 1.37, and 0.19 mA · W−1, and 1.68, 2.45, and 1.09 mA · W−1, respectively. The substrate temperatures after 1 min of 1 kV and 3 kV EBI were 102 °C and 591 °C, respectively. The WS2-based photodetectors exhibited high responsivity in the visible light region despite their unique process conditions of low temperature and fast EBI treatment. Such desirable performance of the EBI-treated WS2 films shows significant potential for future large-area and low-temperature photoelectronic applications. Thus, we demonstrated that EBI is an attractive method for synthesizing 2D materials as it is fast, simple, controllable, and compatible with sputtering processes.

WS2/WO3 Heterostructure-Based Photodetectors on SiO2/Si for Future Optoelectronics

“…The UV–visible photodetector parameters, such as R λ , D *, and EQE of WO 3 , WS 2 , and WS 2 /WO 3 samples, are provided in Table . Further, to benchmark the fabricated test device performance, the comparison of FOM with the reported photodetectors ,,− based on TMDs has been made and given in Table . It divulges that the achieved results from the current investigation on the WS 2 /WO 3 heterostructure show the enhanced photodetector performance even at lower power density.…”

Ultralow Dark Current (6 fA at 1 V) in Quasi-Two-Dimensional CsGaGeSe4 Single Crystals for High Signal-to-Noise Ratio Photodetectors under Strong Electron Localization

“…At a bias voltage of 10 V, the detector demonstrates a dark current of approximately 60 fA, with a calculated resistance of roughly 1.6 × 10 14 Ω. Its dark current density J dark is about 10 –9 A cm –2 , which is several orders of magnitude lower than that of most detectors. − It is noteworthy that the ultralow dark current density can be attributed to the inherent physical properties of CsGaGeSe 4 , underscoring the significant potential of the material of working for weak-light detection.…”

“…Dark current density of the CsGaGeSe 4 -based photodetector and other reported devices. − The ordinate is shown with a logarithm. The inset presents the dark current density of the device in normal coordinates, displaying an ohmic contact between the single crystal and the metal electrode.…”

Electrodeposited WS2 monolayers on patterned graphene

“…The challenges associated with scaling the production of 2D material heterostructures present a major obstacle that hinders their adoption in industry. There are several scalable techniques that have been used to deposit WS 2 , such as chemical vapor deposition (CVD), atomic layer deposition, plasma sputtering, pulsed laser deposition, thermal decomposition, liquid exfoliation and electrodeposition [7,[16][17][18][19][20][21][22]. Among these, CVD stands out because it can controllably deposit monolayer of various TMDC materials with very high crystallinity.…”