Compositional variations in In0.5Ga0.5N nanorods grown by molecular beam epitaxy

The composition of InxGa(1-x)N nanorods grown by molecular beam epitaxy with nominal x = 0.5 has been mapped by electron microscopy using Z-contrast imaging and x-ray microanalysis. This shows a coherent and highly strained core-shell structure with a nearatomically sharp boundary between a Ga-rich shell (x similar to 0.3) and an In-rich core (x similar to 0.7), which itself has In-and Ga-rich platelets alternating along the growth axis. It is proposed that the shell and core regions are lateral and vertical growth sectors, with the core structure determined by spinodal decomposition.