Ultraviolet lasing action in ZnO nanosheets

Area of Science:

• Materials Science
• Optoelectronics
• Solid-State Physics

Background:

• Zinc oxide (ZnO) is a promising semiconductor material with unique optical and electronic properties.
• Developing efficient ultraviolet (UV) light sources is crucial for various technological applications.
• Room-temperature operation is highly desirable for practical laser devices.

Purpose of the Study:

• To investigate the potential of ZnO nanosheets as a gain medium for UV lasing.
• To achieve and characterize room-temperature ultraviolet lasing action in ZnO nanosheets.
• To explore the underlying mechanisms responsible for the observed lasing behavior.

Main Methods:

• Synthesis of uniform multilayer ZnO nanosheets using a vapor-transport method via thermal evaporation of Zn powder.
• Characterization of the synthesized ZnO nanosheets.
• Optical pumping experiments to induce and measure lasing emission.

Main Results:

• Demonstrated room-temperature ultraviolet lasing action in ZnO nanosheets.
• Observed multimode lasing emission centered at 390 nm with a mode linewidth < 0.33 nm.
• Lasing occurred above an excitation threshold of 8 mJ/pulse/cm².
• Attributed multimode lasing to microcavity effects and low defect concentration.

Conclusions:

• ZnO nanosheets are viable gain media for UV semiconductor lasers.
• Further optimization, such as achieving completely uniform nanosheets, may lead to single-mode lasing.
• This work paves the way for practical UV diode lasers based on ZnO nanostructures.