Improving the luminous efficiency of red nanocolumn μ-LEDs by reducing electrode size to ϕ2.2 μm

Abstract

A red InGaN-based nanocolumn micro μ LED with an emission diameter of ϕ 2.2 μ m was demonstrated to achieve an on-wafer external quantum efficiency (EQE) of 2.1% at the peak wavelength of 615 nm. The LED was fabricated by repeating the electrode process on the same nanocolumn pattern area and reducing the emission diameter from ϕ 80 to ϕ 2.2 μ m. The peak EQE, which was maximized at ∼25 A cm ^−2 , increased by decreasing the emission diameter from 1.2% to 2.1%. This behavior, which differs from that of InGaN-film LEDs, is characterized as a unit of independent nano-LEDs with passivated sidewalls of nanocolumn LEDs.

Keywords

• red μ-LED
• InGaN
• nanocolumns
• high on-wafer EQE
• nanowires
• nanocolumn μ-LEDs