Areal density control of ZnO nanowires in physical vapor transport using Ge nanocrystals

Abstract

We revealed the most significant parameter determining an areal density of nanowires (NWs) in physical vapor transport. Seed layer characters such as the crystallinity and the surface roughness can affect the NW growth. We controlled the surface roughness and the crystallinity of seed layers both by annealing process and using Ge nanocrystals. With increase of the surface roughness of seed layers, the areal density of NWs increased, which was independent of the crystallinity of seed layers. Therefore, the large surface roughness was considered to be a critical parameter for high areal density of NWs. This study demonstrated that the substrate with well-controlled surface roughness brought control of an areal density of NWs. This well-controlled technique of NW areal density will open for the next generation NW devices.

Quantitative spatial mapping of distorted state phases during the metal-insulator phase transition for nanoscale VO 2 engineering

“…Due to their metastable structures and spatial phase inhomogeneities in the film/bulk samples, these structural phases can exhibit different phase transition behaviors and properties. In recent years, a wide range of device applications involving miniaturization using nanostructures and nanofilms of oxides have been expanding [ 24–26 ]. Precise control of domain structures and phase transitions at the single domain level is also expected for VO 2 materials, and the development of a method to precisely characterize the phase structure of VO 2 at the nanoscale is a major challenge [ 27 ].…”