On the Growth of InGaN Nanowires by Molecular-Beam Epitaxy: Influence of the III/V Flux Ratio on the Structural and Optical Properties

In this study, for the first time, the influence of the III/V flux ratio on the structural and optical characteristics of InGaN nanowires grown by plasma-assisted molecular beam epitaxy are investigated. It is found that the formation of InGaN nanowires with a core–shell structure occurs when the III/V flux ratio (taking into account the In-incorporation coefficient) is about 0.9–1.2. At the same time, an increase in the III/V flux ratio from the intermediate growth conditions to metal-rich conditions leads to a decrease in the In content in nanowires from ~45 to ~35%. Samples of this type exhibit photoluminescence at room temperature with a maximum in the range from 600 to 650 nm. A further increase in the III/V flux ratio to ~1.3 or its decrease to ~0.4 lead to the formation of merged nanocolumnar layers with a low In content. The results obtained may be of interest for studying the growth processes of InGaN nanowires and creating RGB light-emitting devices based on them.