Super-aligned carbon nanotubes patterned sapphire substrate to improve quantum efficiency of InGaN/GaN light-emitting diodes.

In this paper, the high performance GaN-based light-emitting diodes (LEDs) on carbon-nanotube-patterned sapphire substrate (CNPSS) by metal-organic chemical vapor deposition (MOCVD) are demonstrated. By studying the mechanism of nucleation, we analyze the reasons of the crystal quality improvement induced by carbon nanotubes (CNTs) in different growth process. Combining with low temperatures photoluminescence (PL) measurements and two-dimensional (2D) finite difference time-domain (FDTD) simulation results, we conclude that the improvement of optical properties and electrical properties of CNPSS mainly originates from the improvement of the internal quantum efficiency (IQE) due to decreased dislocation density during nano-epitaxial growth on CNPSS.