Realization of Highly Efficient InGaN Green LEDs with Sandwich-like Multiple Quantum Well Structure: Role of Enhanced Interwell Carrier Transport

Abstract

The potential of multicolor semiconductor electroluminescence in solid-state lighting has been extensively pursued due to the energy-saving and smart-lighting as compared to conventional phosphor-converted white light sources. Here, we demonstrate a highly efficient 525 nm GaN-based green light-emitting diode (LED) with a sandwich-like multiple quantum well (MQW) structure grown on patterned Si(111) substrates. Performance enhancement can be achieved by adjusting the thicknesses of the three quantum barriers close to p-GaN in the interior of the sandwich MQW. Samples A, B, and C, with an optimized barrier thickness of 13, 10, and 8 nm, showed peak external quantum efficiency (EQE) values of 55.6%, 56.2%, and 49.0%, respectively. Under normal working conditions (350 mA, current density 35 A/cm2), the output power, EQE, forward voltage, and dominant wavelength of the sample representing the best performance were 306.0 mW, 37.0%, 2.76 V, and 525 nm, respectively. This work might provide an economically feasible way to realize volume-produce of highly efficient InGaN green LEDs on silicon substrates.

Absorption and emission modulation in a MoS2–GaN (0001) heterostructure by interface phonon–exciton coupling

“…The broadband light emitters can be constructed based on ternary compounds such as indium gallium nitride (InGaN) formed from III-V bulk semiconductors, which offer tunable band gaps from 3.4 eV (GaN) to 0.64 eV (InN) [4], [5]. However, a high In content required to generate red or near-infrared light decreases the efficiency of light generation due to In segregation and a higher defect density resulting from the lattice mismatch with the substrate [6]. These problems can be overcome by developing novel 2D-3D heterostructures based on GaN interfaced with transition metal dichalcogenides (TMDs) which have lattice constant similar to GaN [7].…”

High External Quantum Efficiency Green Light Emitting Diodes on Stress-Manipulated AlNO Buffer Layers

“…Moreover, the AlN thin films prepared using the PVD sputtering without oxygen incorporation had a hexagonal wurtzite structure. A small peak of the γ-Al 2 O 3 (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31) plane was observed (yellow dotted line) when the O 2 flow rate was 1 sccm (Buffer B) [20]. With an increasing O2 flow rate, the diffraction peaks of AlN (0002) gradually merged with the small peak of γ-Al 2 O 3 (12-31) plane, indicating the infusion of oxygen in the AlN structure of the hexagonal system.…”

“…Furthermore, the contrasting thermodynamic and structural properties of InN and GaN lead to low miscibility, making it difficult to grow highquality green-emitting InGaN/GaN multiple quantum wells (MQWs) [9]. Several methods have been used to improve the EQE of green LEDs, such as the use of pattern sapphire substrates, non-polar or semi-polar substrates [10], AlGaN ternary quantum well protective layers [11,12], sandwich MQW growth process [13,14], and controlling the strain, field, electronic band mechanism to reduce the influence of QCSE [15,16]. The EQE of the green LEDs has been improved to reach 40%.…”

Green InGaN Quantum Dots Breaking through Efficiency and Bandwidth Bottlenecks of Micro‐LEDs

“…[ 1 ] The external quantum efficiencies (EQEs) of current blue, green, and yellow LEDs based on InGaN quantum well (QW) are as high as 80%, 50%, and 30%, respectively. [ 2–7 ] However, several bottlenecks exist in utilizing them for some emerging applications beyond lighting, such as micro‐LED display and high‐speed visible‐light communication (VLC). Over the past decade, micro‐LEDs with a chip size below 100 µm (especially below 50 µm) have attracted considerable attention as the most promising next‐generation display technology after LCD and organic LEDs (OLEDs).…”