Ubiquitous Organic Molecule-based Free-standing Nanowires with Ultra-high Aspect Ratios

Abstract

The critical dimension of semiconductor devices is approaching the single-nm regime, and a variety of practical devices of this scale are targeted for production this decade. Planar structures of nano-devices are still the center of fabrication techniques, which limit further integration of devices into a chip. Extension into 3D space is a promising strategy for future device integration; however, the steep increase in the number of surfaces and their interaction in 3D nanospace make it hard to integrate nanostructures with aspect ratios over ~ 10. We report herein a unique technique to produce uniform free-standing 1D nanostructures with extremely high aspect ratios over 100, borrowing from technology developed for cancer radiotherapy with high-energy charged particles. Along the straight trajectory of particles penetrating the condensed phase of a variety of sublimable organic molecules, 1D nanowires were formed with single-nm thickness and perfectly controlled length. An all-dry process was developed to isolate the nanowire plexus, and hetero-junction structures could be facilely built into the nanowires by the new technique. Coaxial extension of nanowires by a chemical process allowed us to freely design the nanowires both in axial and radial directions.

Enhanced terahertz emission from mushroom-shaped InAs nanowire network induced by linear and nonlinear optical effects

“…Structural controlled semiconductors are an accessible and practical method to improve their THz emission performance. For example, nanowires (NWs) have shown electrical and optical properties due to their unique onedimensional structure [18][19][20]. As a THz emission material, semiconductor NWs have attracted great research attention because their low dimensional structure and large surface-tovolume ratio can break through the total-internal reflection limitation of the THz radiation generated by dipole radiation in bulk materials [21,22], thus increasing the THz emission efficiency.…”