Charge transfer between semiconductor nanocrystals and a metals

Abstract

A (sub) monolayer of semiconductor dots is deposited on a metal electrode. This system is used as working electrode in a photoelectrochemical cell. With time-resolved photoelectrochemistry we are able to determine the rate constants of photoinduced electron tunneling between the quantum dots and the metal. By using self-assembled monolayers (SAM) of spacer molecules with different lengths. The distance dependence of electron tunneling was studied.

In the second part, the system was used for tunneling spectroscopy. When an STM tip is positioned above a single quantum dot, a double barrier tunnel function is formed. We found that the symmetry of this junction plays an important role in the interpretation of the tunneling spectra. Furthermore, we have measured the single-electron energy spectrum of a dot by using a very asymmetrical function.