Theoretical analysis of a white-light LED array based on a GaN nanorod structure.

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• Indium Gallium Nitride (InGaN)/Gallium Nitride (GaN) quantum wells are crucial for light-emitting diodes (LEDs).
• Achieving white light emission often relies on phosphors, which can impact efficiency and color stability.
• Nanostructure engineering offers new pathways for tailored optoelectronic properties.

Purpose of the Study:

• To design and simulate a phosphor-free white-light LED utilizing a two-section GaN nanorod (NR) structure.
• To control the In content distribution within InGaN/GaN quantum wells on the NR sidewall.
• To achieve white light by mixing blue and yellow emission components through precise NR geometry design.

Main Methods:

• Experimental demonstration of In content distribution in InGaN/GaN quantum wells on GaN NR sidewalls.
• Theoretical modeling of In diffusion length and incorporation ratio dependencies on NR geometric variables (height, radius, tapering).
• Simulation of a two-section GaN NR LED structure for white light generation.

Main Results:

• The designed NR geometry effectively controls In distribution, leading to distinct blue and yellow emission components.
• At low injection current, the higher-In upper NR section emits a stronger yellow component.
• At higher injection currents, current spreads to the lower-In lower section, enhancing blue emission, resulting in mixed white light.

Conclusions:

• The proposed GaN nanorod LED structure offers a viable alternative for phosphor-free white-light generation.
• Precise control over NR geometry is key to tuning In incorporation and achieving desired emission spectra.
• This approach demonstrates the potential of nanostructure engineering for advanced LED applications.