Chemical tension and global equilibrium in VLS nanostructure growth process : from nanohillocks to nanowires

• Published in: Applied physics. A, Materials science & processing Vol. 86; no. 4; pp. 433 - 440
• Main Authors: LI, N, TAN, T. Y, GOSELE, U
• Format: Journal Article
• Language: English
• Published: Berlin Springer 01-03-2007; Springer Nature B.V
• Subjects: Applied physics; Cross-disciplinary physics: materials science; rheology; Crystal growth; Equilibrium; Exact sciences and technology; Gibbs free energy; Materials science; Nanoscale materials and structures: fabrication and characterization; Nanostructure; Nanowires; Other topics in nanoscale materials and structures; Physics; Thickness; Gibbs free energy; Growth mechanism; VLS growth; Contact angle; Nanowires; Nanostructures; Chemical model
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-006-3809-4

We formulate a global equilibrium model to describe the growth of one-dimensional nanostructures in the VLS process by including also the chemical tension in addition to the physical tensions, i.e. surface energies. The chemical tension derives from the Gibbs free energy change due to the growth of a crystal layer of an elementary thickness. The system global equilibrium is arrived at via the balance of the static physical tensions and the dynamic chemical tension. The model predicts and provides conditions for the growth of nanowires of all sizes exceeding a lower thermodynamic limit. The model also predicts the conditions distinguishing the growth of nanohillocks from nanowires. These predictions will allow the verification of the model by future experiments specifically designed for this purpose.