A novel approach for the growth of InGaN quantum dots

Abstract

A novel two-step growth method for creating InGaN quantum dots (QDs) was developed by using a combination of an In x Ga 1-x N nucleation layer with a platelet structure and an In y Ga 1-y N formation layer with an indium content lower than that of the In x Ga 1-x N nucleation layer. The realized QDs were investigated by micro-photoluminescence measurements. We observed sharp emission lines at 4 K with a spectral width down to the spectral resolution limit of the experimental setup of 0.17 meV. This growth concept is discussed in comparison with conventional growth methods.

Microstructural and compositional analyses of GaN‐based nanostructures

“…In addition, TEM analyses indicated the onset of InGaN island dissolution. These problems were overcome by development of a new growth technique for InGaN quantum dot formation [44], where an InGaN nucleation layer of 1-2 nm thickness and nominal concentration of 0.4 is stabilised by an InGaN formation layer of about 7 nm thickness and nominal concentration of 0.1. The capped structure exhibits quantum dot luminescence [45], and TEM analysis revealed that the quantum dot emission most probably stems from indium rich regions with diameters of $5 nm [46].…”

Micro‐photoluminescence studies of InGaN/GaN quantum dots up to 150 K

“…The InGaN is deposited on a GaN buffer at a temperature of 700 °C for which formation of QD structures is theoretically expected. The InGaN QD structure is capped by GaN with a thickness of 30 nm the growth temperature is increased up to 820 °C (for growth details see [11]). Morphological information on the QD structures will be achieved in future by transmission electron microscopy investigations.…”

Optical properties of single InGaN quantum dots and their devices

“…[41,42] A microphotoluminescence (m-PL) setup has been used employing a microscope objective to excite nonresonantly individual mesa structures with a continuous-wave (325 nm) or pulsed laser system (350 nm) and to collect their emission at variable temperatures (the measurements were performed at 4 K unless otherwise stated). The PL emission was detected either by a liquid-nitrogen cooled charged-coupled device camera or a multichannel plate after dispersion in a monochromator.…”