Lithographic in-mold patterning for CsPbBr₃ nanocrystals distributed Bragg reflector single-mode laser.

Area of Science:

• Optoelectronics
• Materials Science
• Nanotechnology

Background:

• Lead halide perovskites are promising gain mediums for lasers.
• Integrating perovskite lasers into optical circuits is challenging due to material fragility during fabrication.
• Existing methods like lithography and etching cause material deterioration, hindering small-scale laser production.

Purpose of the Study:

• To develop a fabrication method for small-size, low-roughness, single-mode perovskite lasers.
• To demonstrate cesium lead bromide (CsPbBr₃) nanocrystal distributed-Bragg-reflector (DBR) waveguide lasers.
• To enable the integration of perovskite lasers into complex optoelectronic circuits.

Main Methods:

• A novel lithographic in-mold patterning method using nanocrystal concentration control and a multi-step filling-drying process.
• Fabrication of CsPbBr₃ nanocrystal laser cavities and DBR gratings without etching or lift-off.
• Demonstration of room-temperature single-mode lasing.

Main Results:

• Achieved the smallest fabricated structures in the few hundred nanometer range.
• Demonstrated single-mode lasing at room temperature with a low threshold of 23.5 μJ cm^-2.
• Obtained a laser output with a narrow full width at half maximum (FWHM) of 0.4 nm.
• Fabricated lasers in a compact array suitable for optoelectronic circuits.

Conclusions:

• The proposed in-mold patterning method overcomes the limitations of traditional fabrication techniques for perovskite lasers.
• This approach enables the creation of high-performance, compact perovskite lasers essential for integrated optoelectronics.
• The developed technique paves the way for advanced perovskite-based photonic devices.