Controllable Growth of Monolayer and Bilayer WSe<sub>2</sub> by Liquid-Phase Precursor via Chemical Vapor Deposition for Photodetection
Two-dimensional WSe<sub>2</sub> nanosheets have received increasing attention due to their excellent optoelectronic properties. Solid precursors, such as WO<sub>3</sub> and Se powders, have been extensively employed to grow WSe<sub>2</sub> nanosheets by the chemic...
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| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-12-01
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| Series: | Nanomaterials |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2079-4991/14/24/2021 |
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| Summary: | Two-dimensional WSe<sub>2</sub> nanosheets have received increasing attention due to their excellent optoelectronic properties. Solid precursors, such as WO<sub>3</sub> and Se powders, have been extensively employed to grow WSe<sub>2</sub> nanosheets by the chemical vapor deposition (CVD) method. However, the high melting point of WO<sub>3</sub> results in heterogeneous nucleation sites and nonuniform growth of the WSe<sub>2</sub> nanosheet. By dissolving WO<sub>3</sub> powder in a NaOH solution, we report a facile and uniform growth of monolayer and bilayer WSe<sub>2</sub> nanosheets on a SiO<sub>2</sub>/Si substrate at a large scale using liquid precursor by the CVD method. The size and thickness of the WSe<sub>2</sub> nanosheets were controlled by modulating the precursor concentration and growth temperature. The as-prepared monolayer and bilayer WSe<sub>2</sub> nanosheets were well characterized by optical microscopy, atomic force microscopy, and Raman and photoluminescence spectroscopy. With the increase in precursor concentration, the size of the monolayer WSe<sub>2</sub> increased up to 120 μm. Bilayer WSe<sub>2</sub> nanosheets were grown at higher temperatures. The photosensitivity of the bilayer WSe<sub>2</sub> was one order of magnitude higher than that of the monolayer WSe<sub>2</sub>. The carrier mobility, specific detectivity, photoresponsivity, and external quantum efficiency of the bilayer WSe<sub>2</sub> were about two orders of magnitude higher than those of the monolayer WSe<sub>2</sub>. Our method opens up a new avenue to grow monolayer and bilayer WSe<sub>2</sub> for optoelectronic applications. |
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| ISSN: | 2079-4991 |