A method to directly synthesize 2D nanomaterials by heating of bulk sources

INV-20015

Background

There exist a multitude of methods for fabricating monolayer nanomaterials, such as chemical methods (including chemical vapor deposition (CVD), vacuum deposition and vaporization, gas condensation, sol‑gel fabrication, electrodeposition), and mechanical methods (including liquid-phase exfoliation (LPE), Scotch‑tape).

The conventional chemical vapor deposition (CVD) has proven to be the most effective method for fabricating high-quality 2D nanomaterials. CVD uses a few precursor reactant chemicals and an inert carrier gas ‑‑ the precursor reactant chemicals evaporate in high temperatures and travel through a long quartz tube into the furnace to make chemical reaction with other precursors and finally create the nanomaterial on a substrate. This conventional method requires a vacuum pump to suck the air out from the tube, and also a controlled amount of two or more precursors, an inert carrier gas with highly controlled flow rates, and a long tube so each precursor can be placed in different parts of the tube, where the temperature of each part of the tube needs to be controlled precisely. These many required components make CVD a difficult and unpredictable method that demands large tools and sophisticated controlling systems.

Technology Overview

The proposed invention involves the direct fabrication of single and multilayered nanomaterials of various types by thermal evaporation under an inert atmosphere. Sources of target nanomaterials are taken in their commercial bulk form, reduced to a powder for convenience and placed on a clean container close to the target substrate inside an inert environment; it is then heated to the desired temperature and held at this temperature for the desired duration. Nanomaterial evaporates from the source and deposits directly on the substrate in the form of well‑formed crystals that can be evaluated for quality or modified for many applications.

This method removes the need for flowing carrier gas (which saves a lot of gas), gas flow controller, several precursor reactants, and temperature controllers for different parts of a long tube during the process, and yields the same quality 2D nanomaterials as CVD but in practice is much simpler and low-cost compared to CVD.

Benefits

- The synthesis setup can be miniaturized, lowering cost

- Multiple types of 2D nanomaterials can be synthesized with the same approach

- Multiple types of substrates can be grown with the same approach

- Alloys and heterostructures can be done through a single-pot growth

- No need for chemical reactions and precursor reactants

- No requirement for carrier gas flow

- Reduced running costs for the synthesis

- Flexibility in furnace designing and power requirements

Applications

- Research laboratories and the semiconductor/nanotechnology industry

- Various electronic and optoelectronic applications