Towards a better understanding of nano‐islands formed during atmospheric pressure MOVPE

Abstract

We report on transmission electron microscopy (TEM) characterisation of nano-islands formed during atmospheric pressure growth of InGaN on GaN by metal-organic vapour phase epitaxy (MOVPE). Although initial results seemed to indicate that three-dimensional InGaN nano-islands had formed, detailed TEM characterisation revealed that the islands do not have a hexagonal crystal structure, and electron energy loss spectroscopy suggests that the observed structures are metallic indium droplets formed during growth, which may be partially nitrided, rather than the expected strain-induced epitaxial InGaN nano-islands.

Insights into the growth mechanism of InxGa1−xN epitaxial nanostructures formed using a silane predose

“…Such arrays, if incorporated into laser diodes (LDs), might also provide an increased density of states near the band edge, and hence enhanced material gain and improved temperature stability [1]. However, the growth of In x Ga 1Àx N QDs by metal-organic vapour phase epitaxy (MOVPE) has proved challenging [2], and a number of different growth routes are being explored, in addition to the exploitation of the Stranski-Krastanov growth mode which has proved successful in molecular beam epitaxy (MBE) [3]. For example Tu et al [4] have exploited a methodology originally developed by Tanaka et al [5] for the growth of nearly lattice-matched GaN/Al x Ga 1Àx N nanostructures to grow very high density layers of In x Ga 1Àx N QDs on GaN.…”