Enhanced Emission Efficiency of Size-Controlled InGaN/GaN Green Nanopillar Light-Emitting Diodes

Nanopillar InGaN/GaN green light-emitting diode (LED) arrays were fabricated by self-assembled Au nanoparticles patterning and dry etching process. Structure size and density of the nanopillar arrays have been modified by varying the Au film thickness in the nanopatterning process. Fabricated nanopillar LEDs have been characterized by both room temperature and temperature-dependent photoluminescence measurements.

A considerable internal quantum efficiency enhancement was achieved which is attributed to the suppressed quantum confined Stark effect derived from the internal strain relaxation. Meanwhile light extraction efficiency can also be enhanced significantly due to the increased light scattering at nanopillar sidewall.

Compared to the planar LED, the nanopillar LED demonstrates the greatest external quantum efficiency enhancement by a factor of 4.08. It is believed that this nanopillar fabrication method can serve as an effective approach to increase the luminescence efficiency of LEDs.