Two-Dimensional Electron-Hole Plasma in Colloidal Quantum Shells Enables Integrated Lasing Continuously Tunable in...

Area of Science:

• Materials Science
• Optoelectronics
• Quantum Optics

Background:

• Integrated optical platforms require efficient, solution-processable light sources.
• Red-emitting materials often suffer from efficiency loss at high excitation due to non-radiative recombination.
• Characterization of red-emitting lasers is crucial for understanding their performance limits.

Purpose of the Study:

• To introduce colloidal quantum shells (QSs) as a solution for efficient red-emitting lasers.
• To investigate the optical gain mechanism in QSs.
• To demonstrate the integration of QSs into on-chip laser devices.

Main Methods:

• Fabrication and characterization of colloidal quantum shells (QSs).
• Investigation of optical gain properties, including gain lifetime and threshold.
• Analysis of emission efficiency at high excitation densities.
• Integration of QSs onto a silicon nitride platform for laser fabrication.

Main Results:

• Optical gain in QSs is mediated by a 2D plasma state, not bound excitons.
• QSs exhibit broad-band, sizable gain across the red spectrum with long gain lifetimes and low thresholds.
• Emission efficiency remains high at high excitation densities due to increased radiative recombination.
• Integrated QS lasers demonstrate high spectral contrast, surface emission, and TE polarization with narrow beam divergence.

Conclusions:

• Colloidal quantum shells provide a viable, processable material platform for overcoming limitations in red-emitting lasers.
• The 2D plasma state in QSs enables efficient and stable light emission, even at high excitation densities.
• QSs are well-suited for realizing high-performance, compact on-chip light sources.