Near-infrared electroluminescence of AlGaN capped InGaN quantum dots formed by controlled growth on photoelectrochemical etched quantum dot templates

Abstract

Near-infrared electroluminescence of InGaN quantum dots (QDs) formed by controlled growth on photoelectrochemical (PEC) etched QD templates is demonstrated. The QD template consists of PEC InGaN QDs with high density and controlled sizes, an AlGaN capping layer to protect the QDs, and a GaN barrier layer to planarize the surface. Scanning transmission electron microscopy (STEM) of Stranski–Krastanov (SK) growth on the QD template shows high-In-content InGaN QDs that align vertically to the PEC QDs due to localized strain. A high-Al-content Al 0.9 Ga 0.1 N capping layer prevents the collapse of the SK QDs due to intermixing or decomposition during higher temperature GaN growth as verified by STEM. Growth of low-temperature (830°C) p-type layers is used to complete the p-n junction and further ensure QD integrity. Finally, electroluminescence shows a significant wavelength shift (800 nm to 500 nm), caused by the SK QDs’ tall height, high In content, and strong polarization-induced electric fields.

Metal–Organic Vapor‐Phase Epitaxy of Semipolar InGaN Quantum Dots Based on GaN V‐Shaped Pits

“…[ 28 ] There are dense “nanostrips” on the sidewalls of the V‐shaped pits (Figure 2b), and its morphology is similar to that of the InGaN WL grown on c ‐plane GaN by the conventional growth interruption method. [ 29 ] It indicates that the InGaN WL on the sidewall forms an InGaN nanostructure after growth interruption but has not yet developed a distinct InGaN QD structure. To explore the cause, the c ‐plane between the adjacent V‐shaped pits is observed by SEM with high magnification, as shown in Figure 2c.…”

Explorations on Growth of Blue-Green-Yellow-Red InGaN Quantum Dots by Plasma-Assisted Molecular Beam Epitaxy

“…Therefore, the growth window for the achievement of long-wavelength self-assembled QDs, that is, the heteroepitaxy of InGaN QDs with high In composition, is very narrow, so it is still a challenge to obtain high quality QDs. Recently, a variety of methods have been adopted to grown red and near-infrared InGaN QDs, including surface pretreatment, introducing the InGaN QW-QD coupled nanostructure, growth interruption method and photoelectrochemical etched quantum dot templates [ 17 , 18 , 19 , 20 ]. Despite such achievements, there remains many challenges to be conquered for self-assembled InGaN QDs, such as wavelength control and quantum efficiency to meet the requirements of actual device application.…”