Summary:
UCLA researchers in the Department of Chemistry & Biochemistry have developed a novel strategy to decouple the interlayer interactions in bulk MoS2 to produce a bulk material with desirable monolayer properties.
Background:
Molybdenum disulfide (MoS2) is a popular and well-studied 2D semiconducting layered material. A single layer, or monolayer, of MoS2 has attractive features for optoelectronic applications, such as a direct bandgap, exciton binding energies over 200 meV, and valley polarization. These features enable MoS2-based devices to potentially be more energy-efficient compared to traditional semiconductor materials. However, MoS2 is limited by the atomic thinness of a monolayer which results in a very delicate material with poor environmental stability. Bulk, multilayer MoS2 is significantly more stable and has an improved ability to absorb photons for optoelectronic process but suffers from a weaker excitonic emission due to interlayer interactions. It is therefore advantageous to decouple interlayer interactions in bulk MoS2 to produce a material with the best properties of both bulk and monolayer MoS2.
Innovation:
UCLA researchers in the Department of Chemistry & Biochemistry have developed a process to dedope multilayer MoS2 and tailor the electron density in molecular-intercalated MoS2. The resulting ‘bulk monolayer’ MoS2 thin films have fully decoupled interlayer interactions and greatly reduced electron concentrations. The excitonic emissions are 20 times stronger than a monolayer and 400 times stronger than bulk. The photoelectronic response is highly improved in the bulk monolayer material, which also displays a high valley polarization ratio not seen in traditional multilayer MoS2.
Potential Applications:
• Optoelectronic devices
• Communications
• Medical equipment
• Laser Sources
Advantages:
• Scalable thin film synthesis
• Greatly increased excitonic emissions
• Enhanced photoluminescence and photoelectric efficiency
• Improved stability over monolayer
• MoS2Well-preserved valley polarization
Development-To-Date:
The bulk monolayer MoS2 has been synthesized and characterized
Related Papers:
Scalable synthesis of bulk monolayer molybdenum disulfide thin films with tailored electron doping
Reference:
UCLA Case No. 2024-022
Lead Inventors:
Yu Huang, Xiangfeng Duan