Single-electron transport in the planar structure of colloidal quantum dots of InSb, PbS, CdSe semiconductors was studied using a scanning tunneling microscope. On the current – ​​voltage characteristics, sections of the current dip were observed similar to the Coulomb gap. Qualitative and numerical comparative estimates suggest that one-electron transport and a phenomenon similar to the Coulomb blockade are observed in the structure of the set of quantum dots. When measuring the current-voltage characteristics, the white-light illumination of the sample breaks the Coulomb blockade, and it can be expected that an instrument element based on such a structure will respond to individual photons. In the region of the Coulomb gap, current oscillations with frequencies in the terahertz range are possible.

Quantum dots of the group of wide-gap and narrow-gap semiconductors are synthesized and investigated under identical conditions, which makes it possible to perform the comparative analysis and modeling of the mechanisms of radiative recombination and luminescence, for which a stable exciton bond between the electron and hole has an important role. Exciton states are unstable for quantum dots without a shell and narrow-gap semiconductors, which leads to a substantial decrease in the probability of radiative recombination and, correspondingly, the quantum yield of luminescence. The experimental values of the spectral position of the luminescence maximum for quantum dots with clear manifestation of the exciton recombination mechanism noticeably shift to the long-wavelength region with respect to the calculated ones. In calculations and analysis, we use the effective electron mass for bulk semiconductors. The observed good correspondence of the calculated values of the maximum and spectral band with the experiment can mean that quantum dots have a long-range order crystalline structure similar to that one observed in single crystals and polycrystals.

Large (up to 20 nm) quantum dots (QD) of indium antimonide were synthesized using colloidal chemistry at elevated temperatures (250-300 °C). In terms of optical and electrophysical characteristics, they exhibit properties similar to those of conventional QD (4-5 nm), with the difference that the spectral maximum of luminescence is shifted inappropriately to the size difference. This, together with measurements of the QD shape by transmission electron microscopy, may indicate a deterioration in the perfection of the crystal structure of large QD, possibly due to insufficient synthesis temperature