Vertically aligned InGaN nanowires with engineered axial In composition for highly efficient visible light emission

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Indium gallium nitride (InGaN) nanowires (NWs) are promising for nanoscale visible light emitters.
• Pristine InGaN NWs often suffer from defects and non-uniform emission due to phase separation.
• Low internal quantum efficiency (IQE) and long radiative recombination times (τr) hinder their performance.

Purpose of the Study:

• To improve the crystalline quality and radiative efficiency of InGaN NWs.
• To develop a method for fabricating InGaN NWs suitable for nanoscale light emitters.
• To investigate the impact of engineered indium content on NW properties.

Main Methods:

• Fabrication of InGaN NWs with uniform In/Ga molar flow ratio (UIF).
• Engineering axial In content by adjusting the In/Ga molar flow ratio during growth.
• Characterization using spatially resolved cathodoluminescence and time-resolved photoluminescence spectroscopy.

Main Results:

• UIF InGaN NWs showed multi-peak white-like emission, defects, and phase separation.
• Engineered InGaN NWs exhibited high luminescence intensity, narrow emission spectra, and enhanced crystalline quality.
• Engineered NWs demonstrated three times higher IQE and shorter τr compared to UIF NWs.

Conclusions:

• Engineering the axial In content is an effective strategy to improve InGaN NW properties.
• Mitigating In fluctuation and crystal defects enhances radiative efficiency and performance for light emitters.
• This approach offers a pathway to high-performance nanoscale visible light emitters.