(Invited) Self-Assembly of Aligned One Dimensional ZnO Nanorod Arrays on Electron Beam Lithographically Patterned Templates for Sensor Applications

Abstract

We have demonstrated the attachment of aligned ZnO nanorod arrays on to the electron beam lithographically patterned oxide surface at lower beam energy. At higher beam energy (~ 20 KeV), the accumulated negative charges that already built on the surface in due course of irradiation restricts the growth of nanorod arrays. This causes a negative shielding potential close to the surface at micron level, and completely unfavorable for the attachment of the negative ZnO carriers. However, at comparatively lower beam energy (~ 5 KeV or less), the secondary electrons are responsible for the pattern with the irradiation zone centered by the local positive field. This allows negatively charged ZnO nanorod arrays to grow at lower beam voltages, which initiate site selective attachments. This protocol of site selection is very useful for various sensor fabrications.

Photochemical Growth of Highly Densely Packed Gold Nanoparticle Films for Biomedical Diagnostics

“…34,35 The relationship between the Gibbs free energy ( G), the nucleation site density (n s ) and the equilibrium concentration of the stable nuclei (N * ) are shown to all directly impact each other in Equation 1. [34][35][36] The surface energy required for the formation of gold nanoparticles comes from this relationship of Gibbs free energy, density of nucleation sites, and the equilibrium concentration of the stable nuclei.…”