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Growth of Single‐Crystalline Wurtzite Aluminum Nitride Nanotips with a Self‐Selective Apex Angle
Author(s) -
Shi S. C.,
Chen C. F.,
Chattopadhyay S.,
Lan Z. H.,
Chen K. H.,
Chen L. C.
Publication year - 2005
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200400324
Subject(s) - materials science , nitride , nanometre , nanotechnology , wurtzite crystal structure , nanoscopic scale , layer (electronics) , pyramid (geometry) , condensation , silicon nitride , catalysis , composite material , optics , zinc , metallurgy , biochemistry , chemistry , physics , thermodynamics
Single‐crystalline, hexagonal aluminum nitride nanotips are fabricated using a vapor‐transport and condensation process (VTCP) on silicon substrates with or without a catalyst layer. The resultant tips have very sharp nanoscale apexes (∼1 nm), while their bases and lengths are up to hundreds of nanometers wide and several micrometers long, respectively. It has been demonstrated that the thickness of the gold‐catalyst layer plays a critical role in controlling the size of the tip; in addition, a catalyst‐free growth mode has been observed, which results in lesser control over the nanotip morphology. Nevertheless, a remarkably narrow distribution of the apex angle of the nanotips, regardless of whether or not a catalyst was used in the VTCP, has been obtained. Compared with the commonly observed ridge and pyramid structures, the nanotips produced by VTCP have higher angles (∼81°) between the tilted (221) and the basal (001) planes that encase it. A mechanism for this self‐selective apex angle in aluminum nitride nanotip growth is proposed.