White emission from non-planar InGaN/GaN MQW LEDs grown on GaN template with truncated hexagonal pyramids

Area of Science:

• Materials Science
• Semiconductor Physics
• Optoelectronics

Background:

• Non-planar semiconductor structures offer unique growth characteristics.
• Gallium Nitride (GaN) based materials are crucial for optoelectronic devices.
• Controlling indium composition in Indium Gallium Nitride (InGaN) is key for tunable emission.

Purpose of the Study:

• To investigate the growth of InGaN/GaN multiple quantum wells (MQWs) on non-planar Gallium Nitride (GaN) templates.
• To analyze the effect of different crystallographic planes on InGaN growth and composition.
• To develop InGaN/GaN MQW light-emitting diodes (LEDs) emitting multiple wavelengths for near-white light generation.

Main Methods:

• Growth of GaN templates with truncated hexagonal pyramids (THPs) via selective-area epitaxy.
• Regrowth of InGaN/GaN MQW structures on THP surfaces using metal-organic chemical vapor deposition.
• Characterization of epitaxial layers using transmission electron microscopy (TEM).

Main Results:

• Successful fabrication of non-planar InGaN/GaN MQW structures on THP arrays.
• Observed variations in growth rates and indium composition of InGaN layers between c-plane and r-plane surfaces of THPs.
• Demonstrated multi-wavelength emission from InGaN/GaN MQW LEDs grown on GaN THP arrays.

Conclusions:

• Non-planar GaN THP templates enable controlled growth of InGaN/GaN MQWs with spatially varying properties.
• The differences in growth characteristics on c-plane and r-plane surfaces lead to multi-wavelength emission.
• This approach offers a pathway towards efficient, single-chip white light-emitting diodes.