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High-Performance and Lithography-Free Au/WS2/Ag Vertical Schottky Junction Solar Cells

Transition metal dichalcogenide (TMD) semiconductors (SCs) exhibit intriguing optical, electrical, and mechanical properties. *

Due to their extraordinarily large optical absorption coefficients, transition metal dichalcogenides (TMDs) are gaining more and more attention for photovoltaic applications. Improving the device performance of a TMD solar cell requires an optimal device architecture and reliable fabrication processes. *

Improving the device performance of a TMD solar cell requires an optimal device architecture and reliable fabrication processes. *

In the article “High-Performance and Lithography-Free Au/WS2/Ag Vertical Schottky Junction Solar Cells” Anh Thi Nguyen, Jun Wang, Eunseo Cho, Seoyoung Lim, Soyeong Kwon, Jungeun Song, Keya Zhou and Dong-Wook Kim describe how they fabricated Au/WS2/Ag vertical Schottky diodes and investigated their photovoltaic characteristics. *

Metal/WS2-multilayer/metal heterojunctions were fabricated using lithography-free processes. 20 nm thick WS2 flakes were exfoliated on template-stripped Ag bottom electrodes, and then 10 nm thick Au top electrodes with a diameter of 2 µm were evaporated on the WS2 surface using holey carbon films as shadow masks. *

Current-sensing atomic force microscope measurements revealed that the Au/WS2/Ag devices exhibit prominent rectifying characteristics, indicating the formation of Schottky diodes. *

The surface morphology and the local current of the samples were simultaneously measured using a current-sensing atomic force microscopy (c-AFM) system in a glove box. For transport measurements with nanoscopic spatial resolution, a wear-resistant highly doped NANOSENSORS™ PointProbe® Plus conductive diamond-coated AFM tip with a typical spring constant of 0.5 N m and a typical resonance frequency of 20 kHz (CDT-CONTR AFM probe type) was employed. *

The power conversion efficiency of the Schottky junction was as high as 5.0%, when illuminated by a light-emitting diode with a peak wavelength of 625 nm and a power density of 2.5 mW cm−2. These devices also possess broadband and incident-angle-insensitive absorption capability due to the very large refractive indices and extremely small thickness of the WS2 flakes. The simple fabrication procedures proposed in the article by  Anh Thi Nguyen et al. demonstrate high-performance and high-yield TMD photovoltaic devices.*

Figure 2 from Anh Thi Nguyen et al. 2023 “High-Performance and Lithography-Free Au/WS2/Ag Vertical Schottky Junction Solar Cells”a) Optical microscope image and b) AFM topographic image of an Au/WS2/Ag device (area: 25 × 25 µm2). b) A height profile from A to A′ along the red line in (a). Dashed lines indicate the thickness of central region of the WS2 flake, 20 nm. The surface morphology and the local current of the samples were simultaneously measured using a current-sensing atomic force microscopy (c-AFM) system in a glove box. For transport measurements with nanoscopic spatial resolution, a wear-resistant highly doped NANOSENSORS™ PointProbe® Plus conductive diamond-coated AFM tip with a typical spring constant of 0.5 N m and a typical resonance frequency of 20 kHz (CDT-CONTR AFM probe type) was employed. *


Figure 2 from Anh Thi Nguyen et al. 2023 “High-Performance and Lithography-Free Au/WS2/Ag Vertical Schottky Junction Solar Cells”
a) Optical microscope image and b) AFM topographic image of an Au/WS2/Ag device (area: 25 × 25 µm2). b) A height profile from A to A′ along the red line in (a). Dashed lines indicate the thickness of central region of the WS2 flake, 20 nm.

*Anh Thi Nguyen, Jun Wang, Eunseo Cho, Seoyoung Lim, Soyeong Kwon, Jungeun Song, Keya Zhou and Dong-Wook Kim
High-Performance and Lithography-Free Au/WS2/Ag Vertical Schottky Junction Solar Cells
Advanced Materials Interfaces 2023, 10, 2300031
DOI: https://doi.org/10.1002/admi.202300031

Open Access: The article “High-Performance and Lithography-Free Au/WS2/Ag Vertical Schottky Junction Solar Cells” by Anh Thi Nguyen, Jun Wang, Eunseo Cho, Seoyoung Lim, Soyeong Kwon, Jungeun Song, Keya Zhou and Dong-Wook Kim is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/.