Preparation method of monolayer molybdenum disulfide thin film

Abstract

The invention discloses a preparation method of a monolayer molybdenum disulfide thin film. The preparation method comprises the following steps: step 1, arranging three temperature zones by using a vacuum tube type furnace, putting powdered sulfur in the temperature zone I, putting nolybdenum trioxide powder in the temperature zone II, putting a substrate at the bottom of a crucible with a cover and then putting the crucible in the temperature zone III; step 2, introducing carrier gas into the vacuum tube type furnace; step 3, heating the temperature zone II to 150-350 DEG C and heating the temperature zone III to 150-350 DEG C; step 4, heating the temperature zone II to 580-800 DEG C to obtain gaseous MoO3-x, wherein x is more than 0 but less than or equal to 1; heating the temperature zone III to 550-750 DEG C; step 5, heating the temperature zone I to 130-220 DEG C to obtain sulfur vapor; heating the temperature zone II to 800-950 DEG C and heating the temperature zone III to 750-900 DEG C; adjusting the flow rate of the carrier gas, carrying the sulfur vapor and the gaseous MoO3-x into a reaction chamber of the crucible through the carrier gas and forming the monolayer molybdenum disulfide thin film on the surface of the substrate. The preparation method disclosed by the invention has the advantage that the substrate is put in the quasi-enclosed crucible, so that the nucleation density of a reaction source is reduced, and the monolayer molybdenum disulfide thin film is obtained.

Description

technical field [0001] The invention relates to the technical field of chemical vapor deposition preparation, in particular to a method for preparing a single-layer molybdenum disulfide thin film. Background technique [0002] As the feature size of devices in silicon-based integrated circuit technology becomes smaller and smaller, the physical limit of devices has been reached. Molybdenum disulfide is a two-dimensional material of transition metal sulfide. As the number of layers decreases to a single layer, its bandgap energy increases from 1.2eV to 1.8eV, from an indirect bandgap semiconductor to a direct bandgap semiconductor. It has the advantages of large specific surface area and increased luminous efficiency. In particular, when molybdenum disulfide is used as the channel material of field effect devices, it exhibits the immune effect of short channel effect, which improves the defects existing in silicon-based devices. Secondly, due to the novel physical propertie...

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Problems solved by technology

Although the mechanical exfoliation method can produce high-quality nanosheets, it cannot obtain large-area molybdenum disulfide films, and the films prepared by physical vapor deposition have low mobility and cannot meet the application requirements of devices.

Chemical vapor deposition can be used to prepare large-area continuous films, but in most methods, the distance between the substrate and the molybdenum source is relatively close, and the evaporation temperature and growth temperature of the molybdenum source cannot be controlled separately, resulting in an increase in the nucleation density on the substrate. The number of layers varies widely

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