Analysis of InGaN-Delta-InN Quantum Wells on InGaN Substrates for Red Light Emitting Diodes and Lasers

Abstract

Modern multi-color RGB micro-light emitting diode (LED) displays and digital micro-mirror laser projectors often require the use of both III-V and III-Nitride material systems for different pixel/laser colors. This is due primarily to the conventionally low efficiencies of red emitters based on the InGaN materials system, which is used to create green and blue emitters for RGB displays. The main challenges for InGaN red emitters are the quantum confined stark effect (QCSE) and the difficulty of incorporating high In-content into the active region. In this work, InGaN/InGaN/delta-InN quantum wells (QWs) on InGaN substrates are proposed and demonstrated to show significant enhancement in electron-hole wavefunction overlap (e_hh) and spontaneous emission radiative recombination rate (Rsp) in the red emission regime. Analysis of InGaN/InGaN/delta-InN QWs with InGaN barriers emitting at 630 nm was performed using a self-consistent six-band • formalism. The e_hh was shown to increase by more than 230% compared to an InGaN/InGaN QW emitting at 630 nm, leading to significant increases in Rsp and internal quantum efficiency (IQE). With growth of InN monolayers on InGaN now readily achievable, this novel active region design could pave the way for high-efficiency, native red-emitting InGaN LEDs and lasers.

Enhancing light extraction efficiency of GaN LED by combining complex‐period photonic crystals with doping

“…Moreover, the surface filling factor is effectively improved due to the introduction of the complex periodic structure, the scale of the grating is reduced, which can enhance the diffraction effect of the thin plane formed by PhCs, and make the photons more conducive to exit. (3) In and Al are doped in the PhC array. These two materials have high practical application value, and further optimization on the basis of past research has far-reaching significance.…”

“…(2) Step 2: By comparing the bandgap widths of triangular and square, single-period and complex-period models, the structure with the largest bandgap is selected as the 3D arrangement structure and then added to the subsequent dual-band simulation. (3) Step 3: The In material is doped in the blue light LED with PhCs, while the Al material is doped in the ultraviolet LED with PhCs. 3D LED models with PhCs are established and initialized structural parameters are set.…”

“…As a third-generation semiconductor material, III-nitrides are widely used in the manufacture of light-emitting diodes (LEDs) in various bands such as blue light and visible ultraviolet light due to their wide bandgap. [1][2][3][4] However, in the blue light band, the positive-negative (PN) junction as an impurity semiconductor has problems such as impurity ionization, excitation scattering, and lattice scattering, resulting in light heat loss. Moreover, the refractive index difference between GaN material and free space is large, 4 resulting in total internal reflection.…”

“…6 These problems have led to the general limitation of the external quantum efficiency of GaN-based flat-panel LEDs in these two wavelength bands. 3,8 At present, many scholars have conducted research on GaN-based LEDs, and many schemes have been proposed, such as: (1) Improving the quantum well in the active region. [9][10][11][12][13] (2) Applying heterostructure capping.…”

“…In addition, P‐type AlGaN has poor conductivity and low doping efficiency, 7 which limits the hole mobility and further leads to low internal quantum efficiency 6 . These problems have led to the general limitation of the external quantum efficiency of GaN‐based flat‐panel LEDs in these two wavelength bands 3,8 . At present, many scholars have conducted research on GaN‐based LEDs, and many schemes have been proposed, such as: (1) Improving the quantum well in the active region 9–13 .…”