Observation of Interlayer Excitons in Mixed-Dimensional MoS₂ and InGaN/GaN Quantum Well Heterojunctions

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Mixed-dimensional heterojunctions (HJs) integrate compound semiconductors and transition metal dichalcogenides (TMDCs) for tunable interfacial exciton dynamics.
• Compound semiconductors offer bandgap tunability but have weak exciton binding energies, limiting room-temperature stability.
• TMDCs provide strong quantum confinement and reduced dielectric screening, enabling stable interlayer excitons with enhanced light-matter coupling.

Purpose of the Study:

• To investigate interlayer exciton behavior in a novel mixed-dimensional heterojunction.
• To demonstrate the formation and characteristics of interlayer excitons at the semiconductor-TMDC interface.
• To explore the potential of such heterojunctions for advanced optoelectronic applications.

Main Methods:

• Fabrication of a mixed-dimensional heterojunction comprising trilayer MoS2 interfaced with an Al2O3/InGaN/GaN single quantum well (QW).
• Utilizing quantum confinement in the QW to localize carriers near the heterointerface.
• Performing low-temperature photoluminescence measurements to detect and analyze excitonic emissions.

Main Results:

• Successful formation of a mixed-dimensional heterojunction between MoS2 and an InGaN/GaN quantum well.
• Observation of quantum confinement effects localizing carriers at the heterointerface.
• Detection of a distinct photoluminescence peak at 2.02 eV, confirming the presence of interlayer excitons.

Conclusions:

• The study demonstrates a viable strategy for creating and observing interlayer excitons in mixed-dimensional heterojunctions.
• This approach enables precise engineering of exciton dynamics at interfaces.
• The findings have significant implications for the development of novel optoelectronic devices utilizing tailored interfacial exciton properties.