In this report, a simple wet chemical etching of ZnO nanorods to fabricate large area ZnO nanocones is demonstrated. The cone-like morphology formation utilizes anisotropic etching rate on the different crystal planes of ZnO nanorods in an aqueous solution of HCl (HCl [aq]). To form ZnO nanocones, single crystalline ZnO nanorods with a flat hexagonal shape are synthesized on p-Si(100) using hydrothermal method at 90 degrees C and then, are immersed in HCl [aq]. Electron microscopy reveals that the HCl [aq] treatment of ZnO nanorods significantly etched sidewalls of nanorods, resulting in the cone-like morphology formation. The nanocone formation is the most noticeable when the etching occurred in HCl [aq] with a pH of 2.5-3.0 for 5 min etching time. Geometrical analysis using the electron microscopy reveals that the sidewall of a ZnO nanocone have formed a plane indexed as (0-111) after the etching process.

The effect of the electmn-elecnon (e-e) interaction on the charge-density wave (cow) of MX complexes is studied using the Cutzwiller variational method within the one-band model, and neglecting the quantum features of the lattice. It is found thal the effect of the e-e intemction on the m w in MX complexes is opposite to that on the BOW (bondader wave) in the conjugated polymer, although both the CDW and BOW have the same origin, which is the dimerization of the one-dimensional lanice. The CDW is suppressed by the ee interaction, and the BOW is initially enhanced. The physical reason for this c o n a t is analysed.