Specifics of MOCVD formation of InxGa1−xN inclusions in a GaN matrix

MOCVD-grown heterostructures with one or several InxGa1−xN layers in a GaN matrix have been studied by transmission electron microscopy. In heterostructures with thick InGaN layers, a noncoherent system of domains with lateral dimensions (∼50 nm) on the order of the layer thickness (∼40 nm) is formed. In the case of ultrathin InGaN inclusions, nanodomains coherent with the GaN matrix are formed. The content of indium in nanodomains, determined by the DALI method, is as high as x≈0.6 or more, substantially exceeding the average In concentration. The density of the nanodomains formed in the structures studied is n≈(2–5)×1011 cm−2. In the structures with ultrathin InGaN inclusions, two characteristic nanodomain sizes are observed (3–6 and 8–15 nm).