Dilute Nitride Nanowire Lasers Based on a GaAs/GaNAs Core/Shell Structure

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Near-infrared nanowire (NW) lasers are crucial for telecommunications, sensing, and medical diagnostics.
• Existing NW lasers utilize materials like GaAs/AlGaAs, GaAs/GaAsP, and InGaAs/GaAs.
• Dilute nitride gallium arsenide nitride (GaNAs) has not been explored for lasing applications.

Purpose of the Study:

• To demonstrate optically pumped lasing in a single GaAs/GaNAs core/shell NW for the first time.
• To characterize the lasing properties, including threshold gain and spontaneous emission coupling factor.
• To investigate the potential of GaNAs for tunable infrared NW lasers.

Main Methods:

• Fabrication of GaAs/GaNAs core/shell NWs.
• Optical pumping experiments to induce and measure lasing.
• Analysis of pump power dependence, emission polarization, and spectral characteristics.
• Theoretical calculations to identify cavity modes.

Main Results:

• Demonstrated optically pumped lasing from the GaNAs shell of a GaAs/GaNAs core/shell NW.
• Observed characteristic "S"-shaped pump power dependence and line width narrowing.
• Determined a threshold gain (g_th) of 3300 cm^-1 and a spontaneous emission coupling factor (β) of 0.045.
• Identified the dominant lasing peak as the HE_21b cavity mode, with emission polarized along the NW axis.
• Sustained lasing up to 150 K without surface passivation, attributed to improved surface quality from nitrogen incorporation.

Conclusions:

• This work presents the first demonstration of lasing in GaNAs-based core/shell NWs.
• The results highlight the potential of dilute nitrides for developing tunable infrared NW lasers.
• Improved surface quality due to nitrogen incorporation contributes to sustained lasing performance.