Single-Electron Emission–Injection Transport in a Microstructure with Colloidal Quantum Dots of Narrow-Gap Semiconductors.

It is shown by approximating the I–V characteristics of colloidal quantum dots of InSb and PbS narrow-gap semiconductors that, in the single-electron mode, electron transport in different voltage ranges is determined by one of the competing processes: emission from a quantum dot, injection into it, or transit through it with current limitation by the space charge. At voltages above 0.5 V, the I–V characteristics of single quantum dots contain current instability and dip portions, similar to the Coulomb gap. Qualitative and numerical comparative estimations suggest that, in the structure of a segregated set of quantum dots, single-electron transport and current limitation similar to the Coulomb blockade are observed. Light exposure during measurements of the I–V characteristics disrupts or enhances the effect and increases or decreases the current, depending on the excitation-radiation spectrum. [ABSTRACT FROM AUTHOR]