Blending of nanoscale and microscale in uniform large-area sculptured thin-film architectures

Abstract

The combination of large thickness ($>3$ $\\mu$m), large--area uniformity (75\nmm diameter), high growth rate (up to 0.4 $\\mu$m/min) in assemblies of\ncomplex--shaped nanowires on lithographically defined patterns has been\nachieved for the first time. The nanoscale and the microscale have thus been\nblended together in sculptured thin films with transverse architectures.\nSiO$_x$ ($x\\approx 2$) nanowires were grown by electron--beam evaporation onto\nsilicon substrates both with and without photoresist lines (1--D arrays) and\ncheckerboard (2--D arrays) patterns. Atomic self--shadowing due to\noblique--angle deposition enables the nanowires to grow continuously, to change\ndirection abruptly, and to maintain constant cross--sectional diameter. The\nselective growth of nanowire assemblies on the top surfaces of both 1--D and\n2--D arrays can be understood and predicted using simple geometrical shadowing\nequations.\n