TY - JOUR

T1 - The origin of shape, orientation, and structure of spontaneously formed wurtzite GaN nanorods on cubic Si(001) surface

AU - Shetty, Satish

AU - Kesaria, Manoj

AU - Ghatak, J.

AU - Shivaprasad, S. M.

PY - 2013/6

Y1 - 2013/6

N2 - We elucidate the atomistic level details of the formation of 1-D GaN nanostructures on Si(001) by molecular beam epitaxy. In a multitechnique study, we understand the epitaxy and role of the unintentional interfacial SiNx layer in determining the shape, structure, and organization of the nanofeatures. The 1-D GaN features are seen to be m-faceted and grow along the Si(111) planes and thus are tilted with a 4-fold symmetry on the cubic Si(100) surface. The interfacial mismatch induced dislocations are shown to provide the nucleation centers for the spiral 1-D growth, while their local density determines their evolution into solid rods, tubes, or c-tubes. The unintentional interfacial nitridation of the substrate forms discontinuous amorphous mounds that provide the epitaxial contact to the substrate and also laterally isolate the rods/tubes, enabling them to grow laterally in their equilibrium hexagonal wurtzite structures. We consolidate the results into a schematic model to unveil the underlying mechanism and demonstrate the subtle relationship between the kinetics of growth and the interfacial properties.

AB - We elucidate the atomistic level details of the formation of 1-D GaN nanostructures on Si(001) by molecular beam epitaxy. In a multitechnique study, we understand the epitaxy and role of the unintentional interfacial SiNx layer in determining the shape, structure, and organization of the nanofeatures. The 1-D GaN features are seen to be m-faceted and grow along the Si(111) planes and thus are tilted with a 4-fold symmetry on the cubic Si(100) surface. The interfacial mismatch induced dislocations are shown to provide the nucleation centers for the spiral 1-D growth, while their local density determines their evolution into solid rods, tubes, or c-tubes. The unintentional interfacial nitridation of the substrate forms discontinuous amorphous mounds that provide the epitaxial contact to the substrate and also laterally isolate the rods/tubes, enabling them to grow laterally in their equilibrium hexagonal wurtzite structures. We consolidate the results into a schematic model to unveil the underlying mechanism and demonstrate the subtle relationship between the kinetics of growth and the interfacial properties.

U2 - 10.1021/cg4000928

DO - 10.1021/cg4000928

M3 - Journal article

VL - 13

SP - 2407

EP - 2412

JO - Crystal Growth and Design

JF - Crystal Growth and Design

SN - 1528-7483

IS - 6

ER -