Layered transition metal dichalcogenides (LTMD), such as MS2, have applications in flexible electronics and optoelectronics, hybrid heterostructures with 2D materials, advanced semiconductor devices and integrated circuits, short-channel devices, valleytronics devices, battery and supercapacitors, and energy harvesting issues such as water splitting and hydrogen production.
The synthesis of high-quality LTMD monolayers remains a great challenge. Additionally, a robust transfer technique to avoid degradation in quality and contamination is essential for fundamental physics and optoelectronic applications. The inventors directly synthesize high-quality MS2 monolayers on various surfaces using a scalable APCVD process and seeding techniques. Not only is the growth successful for surfaces of different materials but the deposition is applicable for surfaces with various morphology. The as-synthesized MS2 monolayer exhibits single crystalline structure with a specific flake shape even on amorphous surfaces.
Aromatic molecules, including reduced graphene oxide (r-GO), PTCDA, and PTAS are used as a seeding layer on diverse surfaces. The aromatic seeds are suspended or solute in DI water and the optimized concentration for growth of MoS2 monolayer is increased with growth temperature. Prior to the surface treatment, the samples are cleaned with piranha solution for making surface. Prior to the synthetic process, the substrates are treated with the seeds solution. A monolayer of MoS2, or some metal dichalcogenide, is grown via chemical vapor deposition on the growth substrate surface seeded with aromatic molecules. The seeded aromativ molecules are contacted with a solvent that releases the metal dichalcogenide layer from the growth substrate. The metal dichalcogenide layer can be released with an adhered transfer medium and can be deposited on a target substrate using PDMS and a tiny droplet of DI water.
- Numerous novel performances and unique optical properties are observed on the LTMD monolayer
- Direct growth of LTMD monolayer on divers surface nanostructures
- Scalable fabrication of high-quality LTMD monolayer
- Simple and low cost
- Low growth temperature
- No limitation on substrate