STUDY OF CONDUCTION MECHANISM AND SCANNING TUNNELING SPECTRUM OF NANO-CaCO₃

We have experimentally found out that an obvious tunnel current begins to appear between nano-CaCO₃ film and tip of STM when the bias voltage reaches 0.6V, above which there is a non-linear rise quickly. We further measure the scanning tunneling spectrum (STS) of nano-CaCO₃ and analyze it compared to that of Au and Silicon. The results show that CaCO₃, an insulating material, after nanometer processing presents a characteristic similarly to a metal, and the constraint to electrons is even smaller than a semiconductor. STS has not only well explained the spectroscopic mechanism of conducting performances of nano-CaCO₃, but also expanded applications of STM to one of the most important research areas. Moreover, the method can be applied to the study of the structure of superconductive materials and energy spectrum characterization.