Branching characteristics of GaN multipods grown by using hydride vapor phase epitaxy

GaN multipods were grown on c-plane sapphire substrates by using hydride vapor phase epitaxy (HVPE) and their branching characteristics were investigated by utilizing scanning electron microscopy. A catalyst-free vapor-solid growth mechanism gave rise to diversity in the formation of multipods in various structures. We found that the core structure primarily determined the branching configuration of the sideward GaN nanorods. Depending on whether the core had a zincblende structure or wurtzite structure, either 3-fold symmetric multipods without a vertical nanorod or 6-fold multipods were favorably grown.