No abstract

We report intrinsic current-voltage properties of ZnO nanowire measured by a four-tip scanning tunneling microscopy (F-STM). It is found that after bending the nanowire with the F-STM the conductance is reduced by about five orders of magnitude. The cathodoluminescent spectra indicate that the ZnO nanowires contain a sizable amount of defects in the surface region, responsible for their conduction. It is suggested that the observed huge conductance changes are caused by the shifting of the surface defect states in the ZnO nanowires in response to the applied surface strain.

We introduce a new type of ZnO array structure that can effectively suppress the reflection of light at a range of wavelength from ultraviolet through visible part to the near-infrared region, with reflectivity <2.5%, resulting in its black color. This black ZnO is composed of a random pyramidal array growing directly on Zn foil through a simple hydrothermal method. We have investigated the causes of antireflection by removing the pyramid tips via scratching and ion etching on the ZnO surface. All results demonstrate that the antireflection nature of the black ZnO originates from the pyramidal array structure, which causes a gradient change of refractive index between air and substrate.