Morphology control of gallium nitride grown on silicon nanoporous pillar array: From cone-strings to nanowires

摘要

Fascicle arrays of gallium nitride (GaN) nanostructures were grown on silicon nanoporous pillar array (Si-NPA) by a reactive chemical vapor deposition method. Through adjusting the distance between the gallium source and Si-NPA substrate, the morphology of GaN nanostructures was tuned from cone-strings, cone-strings plus nanowires to nanowires, accompanied with the average diameter changed from ~800 nm to ~ 13 nm. Both the cone-strings and the nanowires were found growing along [0001 ] direction. These results indicate that Ga concentration is a key factor in determining both the morphology and the average diameter of GaN nanostructures. The growing process of the GaN nanostructures was explained under the frame of vapor-liquid-solid deposition mechanism. Our method might be expanded to the growth of other compound semiconductor nanostructures on patterned silicon substrates for constructing functional nanodevices.