Recent Progress in GaN‐Based Light‐Emitting Diodes

Abstract

In the last few years the GaN‐based white light‐emitting diode (LED) has been remarkable as a commercially available solid‐state light source. To increase the luminescence power, we studied GaN LED epitaxial materials. First, a special maskless V‐grooved c‐plane sapphire was fabricated, a GaN lateral epitaxial overgrowth method on this substrate was developed, and consequently GaN films are obtained with low dislocation densities and an increased light‐emitting efficiency (because of the enhanced reflection from the V‐grooved plane). Furthermore, anomalous tunneling‐assisted carrier transfer in an asymmetrically coupled InGaN/GaN quantum well structure was studied. A new quantum well structure using this effect is designed to enhance the luminescent efficiency of the LED to ∼72%. Finally, a single‐chip phosphor‐free white LED is fabricated, a stable white light is emitted for currents from 20 to 60 mA, which makes the LED chip suitable for lighting applications.

Near‐Infrared Light Emission from a GaN/Si Nanoheterostructure Array

“…As is known, gallium nitride (GaN) is a direct wide-bandgap semiconductor with high carrier mobility and high thermal and chemical stability, and which has been widely utilized in green, blue, and ultraviolet LEDs. [ 13 ] Singlecrystal silicon ( sc -Si) is still the base of the modern electronic industry and has asserted its dominance in large-scale device integration. If NIR EL could be obtained by tailoring the electronic structure and controlling the carrier recombination path in a carefully designed GaN/Si heterostructure, the combination of the merits of both the materials would make asconstructed NIR LEDs technically and practically competitive.…”

Self-Organized Three-Dimensional Nanostructured Architectures in Bulk GaN Generated by Spatial Modulation of Doping

“…Over the past decades it has played a major role in the development of modern solid-state lighting industry. [1][2][3] An intensive investigation of this compound started in 1970's, but with minimal success in the development of real applications. In the absence of native bulk material, GaN epilayers were grown on foreign substrates and, as a result of the large lattice mismatch and difference in thermal expansion coefficients, the overgrown films contained a high concentration of threading dislocations.…”

Preparation and annealing of GaN/Cu core-shell nanowires

“…Due to its unique properties that include a large direct bandgap, strong interatomic bonds, and high thermal conductivity [8], gallium nitride (GaN) can be used in the formulation of light-emitting and optoelectronic devices [9,10]. Thus, the synthesis of GaN nanowires has been intensively studied [11][12][13][14].…”