Defect-selective-etched porous GaN as a buffer layer for high efficiency InGaN/GaN light-emitting diodes

Area of Science:

• Materials Science
• Optoelectronics
• Semiconductor Physics

Background:

• Substrate-induced stress and threading dislocations (TDs) degrade InGaN/GaN light-emitting diode (LED) performance.
• Developing high-efficiency and reliable LEDs requires mitigating these issues.

Purpose of the Study:

• To investigate the efficacy of a defect-selective-etched (DSE) porous GaN layer as a buffer for InGaN/GaN LEDs.
• To enhance the quantum efficiency and reliability of InGaN/GaN LEDs.

Main Methods:

• Fabrication of a DSE porous GaN layer using electrochemical etching.
• Growth of InGaN/GaN heterostructures on the DSE porous GaN buffer layer.
• Analysis using photoluminescence and micro-Raman spectroscopy.

Main Results:

• The overgrown GaN epilayer on the DSE porous GaN exhibited significantly lower TDs and reduced compressive stress compared to conventional GaN.
• A notable improvement in the internal quantum efficiency of InGaN/GaN LEDs was observed.
• Enhanced radiative recombination in InGaN/GaN multi-quantum-wells due to stress relaxation and TD annihilation.

Conclusions:

• The DSE porous GaN buffer layer effectively reduces stress and TDs in GaN epilayers.
• This approach offers a viable strategy for producing high-performance InGaN/GaN LEDs with improved crystalline quality and efficiency.