The Transport of Electrons through Tetrapod-Shaped CdTe/CdSe Nanocrystals

Abstract

A quasi-one-dimensional model was developed for the transport of electrons in the scanning tunneling microscope needle–CdTe/CdSe tetrapod-shaped nanocrystal system. This model was used as a basis to study the effect of the concentration of charge carriers in the tetrapod and its energy band structure, the geometry, and the spatial orientation with respect to the substrate on the voltage–current characteristics. The major classes of voltage–current characteristics that could be experimentally measured were determined by numerical modeling. The thus-determined classes of voltage–current characteristics were immediately related with the spatial orientation and sizes of tetrapods. This classification of voltage–current characteristics was used to separate the voltage–current characteristics, which corresponded to the transport of electrons from the scanning microscope needle through the tetrapod into the substrate, from the array of previously measured characteristics. The numerically calculated and experimental characteristics were compared with each other to determine the best-fit parameters of this model.