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

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 highAl-content A1_(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℃)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.