High performance electron blocking layer-free InGaN/GaN nanowire white-light-emitting diodes

Abstract

We investigated the effect of coupled quantum wells to reduce electron overflow in InGaN/GaN dot-in-a-wire phosphor-free white color light-emitting diodes (white LEDs) and to improve the device performance. The light output power and external quantum efficiency (EQE) of the white LEDs with coupled quantum wells were increased and indicated that the efficiency droop was reduced. The improved output power and EQE of LEDs with the coupled quantum wells were attributed to the significant reduction of electron overflow primarily responsible for efficiency degradation through the near-surface GaN region. Compared to the commonly used AlGaN electron blocking layer between the device active region and p-GaN, the incorporation of a suitable InGaN quantum well between the n-GaN and the active region does not adversely affect the hole injection process. Moreover, the electron transport to the device active region can be further controlled by optimizing the thickness and bandgap energy of this InGaN quantum well. In addition, a blue-emitting InGaN quantum well is incorporated between the quantum dot active region and the p-GaN, wherein electrons escaping from the device active region can recombine with holes and contribute to white-light emission. The resulting device exhibits high internal quantum efficiency of 58.5% with highly stable emission characteristics and virtually no efficiency droop.

Enhancing optical properties of WLEDs with LaOF:Eu3+&SiO2 application

“…In recent studies, the quantum yield of Sr4Al14O25 [13]; Ca14Al10Zn6O35 [14]; CaAl12O19 [15]; Sr4Al14-O25:Mn 4+ [16] is estimated to be 38%, 50%, 35.5%, 60.8% under 450 nm blue light excitation, and 166% respectively [17];. The trivalent luminous lanthanide (Ln 3+ ) ions, which have a comparable ion radius to composite particles, are reasonably easy to mix to the particle configuration and provide good lighting performance even at ambient temperature [18]- [21]. The most notable ion in RE particles' research is Eu 3+ , which can act as the best material for the creation of red light [22].…”

Fabrication of ultra‐thin alumina membranes utilizing waste aluminum cans

“…[20] Currently, energy conversion devices were fabricated base on high-crystalline quality III-nitride nanowires developed on silicon wafer via selective area growth approach by molecular beam epitaxy technique. [21][22][23] However, high-cost template preparation of lithography method has limited its application in nano-structural fabrications. Anodic aluminum oxide (AAO) porous membranes are utilized as low-cost hard-templates to prepare homogeneous nanostructures such as nanotubes, nanowires and nanodots.…”

Improved Performance of Electron Blocking Layer Free AlGaN Deep Ultraviolet Light-Emitting Diodes Using Graded Staircase Barriers

“…In this regard, different EBL-free LED designs have been studied for III-nitride semiconductor LEDs. Linear graded quantum barrier (QB)-based EBL-free AlGaN UV LEDs with similar optical performance compared to conventional EBL LEDs [12], strip-in-a-barrier AlGaN UV LEDs without EBL with remarkably high performance compared to regular EBL LEDs [13], band engineered EBLfree AlInN UV LEDs [14], lattice-matched InGaN/AlInN/InGaN QB visible LEDs without EBL [15], EBL-free coupled quantum wells (QWs) based InGaN/GaN nanowire LED for white light emission [16] are some of the reported studies. However, to-date, a study on high-performance EBL free AlGaN deep UV LEDs is limited.…”