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

Substrate-induced biaxial compressive stress and threading dislocations (TDs) have been recognized to severely impair the performance, stability, and reliability of InGaN/GaN light-emitting diodes (LEDs) for quite some time. In this study, a defect-selective-etched (DSE) porous GaN layer is fabricated employing electro-chemical etching and applied as a buffer layer for the development of InGaN/GaN LEDs with high quantum efficiency. Based on the analysis of photoluminescence and micro-Raman spectra, it has been revealed that the overgrown GaN epilayer on the DSE porous GaN has a relatively low TDs and relaxation of compressive stress in comparison to the conventional GaN epilayer. The remarkable improvement in the internal quantum efficiency of the InGaN/GaN LEDs is directly attributable to the strong radiative recombination in InGaN/GaN multi-quantum-wells caused by stress relaxation and TDs annihilation. Our findings indicate that the use of DSE porous GaN as a buffer layer may be a viable approach for producing crystalline GaN epilayers and high-performance LEDs.

Automated summary

This study demonstrates the use of a defect-selective-etched (DSE) porous GaN layer as a buffer layer for InGaN/GaN LED development. The overgrown GaN epilayer on the DSE porous GaN exhibits reduced threading dislocations (TDs) and relaxation of compressive stress compared to the conventional GaN epilayer. The enhanced internal quantum efficiency of the InGaN/GaN LEDs is attributed to stress relaxation and TDs annihilation.