Room-temperature conductance spectroscopy of CdSe quantum dots using a modified scanning force microscope

The conductance of isolated CdSe quantum dots (QD’s) of ∼4 nm diameter, epitaxially electrodeposited on gold substrates, has been studied using a scanning force microscope with a metallized tip to perform current-voltage spectroscopy. The band gaps of the dots have been measured and correlated with the QD size distribution. Reproducible peaks in the room-temperature conductance spectra are interpreted as transport of single electrons through the quantum dots. The roles of both Coulomb charging and interlevel spacing are considered.