Glue-free Transfer Method for Fabricating Monolayer Transition Metal Chalcogenide Longitudinal Heterojunctions

Abstract

The invention discloses a method for preparing longitudinal heterojunctions of single-layer transition metal chalcogenides by no-glue transfer. Firstly, fused salt is mixed with transition metal oxide powder as an evaporation source; and transition metal chalcogenides are prepared through growth of the fused salt assisted by a chemical vapor deposition method. Then, de-ionized water is used, and is contacted with the transition metal chalcogenides; the transition metal chalcogenides can float along with water; through flowing of the water, the transition metal chalcogenides are transferred to any target substrate; and the longitudinal heterojunctions and multiple layers of stacked longitudinal heterojunctions are prepared through multiple times of transfer of the transition metal chalcogenides. Any organic glue is not used as a middle auxiliary layer, so that the problem of glue remaining can be solved; and any corrosive solution cannot be used, so that the destruction and the doping of the corrosive solution to the transition metal chalcogenides can be prevented, a new method is provided for transfer of the transition metal chalcogenides and preparation of the longitudinal heterojunctions thereof, and the important significance on acceleration of the research and the application of the transition metal chalcogenides and the longitudinal heterojunctions thereof is achieved.

Description

technical field [0001] The invention relates to indicators of direct bandgap semiconductor materials, in particular to a method for preparing a vertical heterojunction of a single-layer transition metal chalcogenide by non-adhesive transfer. Background technique [0002] As a single-layer transition metal chalcogenide is a direct bandgap semiconductor material, it has important application prospects in energy devices, chemical catalysis, and optoelectronic devices. Combining two or more single-layer transition metal chalcogenides to form a vertically structured heterojunction, the change in the interaction between vertical heterojunctions will provide a new degree of freedom for the exploration of new physical properties of transition metal chalcogenides , to provide new ideas for the design of new electronic devices. Chemical vapor deposition (Chemical vapor deposition, CVD) is the most common method for preparing single-layer transition metal chalcogenides. It is easy to ...

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Problems solved by technology

Generally, chemical vapor deposition can also be used to prepare vertical heterojunctions of transition metal chalcogenides. However, when this method is used to prepare vertical heterojunctions, the preparation results are very sensitive to experimental parameters, which are difficult to control and require a lot of effort. Find the best experimental conditions, and the vertical heterojunction prepared by chemical vapor deposition always has a fixed relative orientation, and the relative angle between the two materials of the vertical heterojunction cannot be adjusted

In addition to the chemical vapor deposition method, we can also use the transfer method to prepare transition metal chalcogenide vertical heterojunctions. It is not only simple and efficient, but also can adjust the relative angle of the vertical heterojunction materials. At present, many methods have been developed. It is used to transfer transition metal chalcogenides and prepare vertical heterojunctions, such as polymethylmethacrylate (PolymethylMethacrylate, PMMA) assisted transfer method, ultrasonic exfoliation transfer method, water molecule infiltration and exfoliation assisted transfer method, etc., but these methods exist Many deficiencies, for example, usually people will use strong acid or strong base to separate the transition metal chalcogenide from the substrate, which will cause serious doping and damage to the transition metal chalcogenide, in addition, people usually use an organic compound as The intermediate auxiliary layer assists in the transfer of transition metal chalcogenides, such as PMMA, etc., but this kind of organic matter is difficult to remove, and it is easy to cause residual glue on the surface of the material

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