Investigation of emission plane control in GaInN/GaN multiple-quantum shells for efficient nanowire-based LEDs

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Core-shell GaInN/GaN multiple-quantum shell (MQS) nanowires (NWs) are crucial for high-efficiency micro light-emitting diodes (micro-LEDs).
• These 3D NWs minimize sidewall etching effects and exhibit low dislocation density with nonpolar or semipolar emitting planes.

Purpose of the Study:

• To investigate the impact of GaInN/GaN superlattice (SL) growth temperature on NW morphology.
• To control the emission plane orientation and size through p-GaN shell growth and emission dimensions.
• To understand how SL structure variations affect light output and efficiency in NW-LEDs.

Main Methods:

• Growing GaInN/GaN SL structures at varying temperatures and gradual temperature transitions.
• Analyzing changes in NW morphology, specifically the (0001) and (11̄01) planes.
• Investigating emission properties of NW-LEDs with varied p-GaN shell growth times and emission sizes.

Main Results:

• Elevated growth temperatures enhanced SL growth rate, shrinking the (0001)-plane and expanding the (11̄01)-plane.
• Samples grown at higher temperatures or with gradual temperature transitions showed increased light output.
• Weak emission from the (0001)-plane was identified as a limiting factor for light output.

Conclusions:

• Controlling NW dimensions, particularly the (0001)-plane, via SL growth is key to influencing NW-LED emission properties.
• Suppressing current injection into the apex or minimizing the (0001)-plane region is essential for high-efficiency devices.
• This approach offers a promising strategy for optimizing NW-LEDs for micro-LED applications.