This paper presents the results of the experimental studies of InAs quantum dot overgrowth by a low-temperature GaAs layer at different arsenic vapor pressures. It is revealed that a threefold decrease in the arsenic pressure at a fixed deposition rate of the capping layer leads to a change in the shape of the photoluminescence spectrum of quantum dots with one maximum at the level of 1.19 eV to the shape of the spectrum with two low-energy contributions at the levels of 1.08 and 1.15 eV. Based on the analysis of the power dependences of the photoluminescence spectra, it is found that the low-energy contributions of the photoluminescence of quantum dots overgrown at a low arsenic pressure correspond to the ground-state emission two groups of quantum dots with different average sizes formed during mass transfer in the “quantum dot – wetting layer – matrix” system.

Photoluminescence spectroscopy (PL) has been used to study the optical properties of three-dimensional quantum-sized InGaPAs islands formed by substituting phosphorus by arsenic in an InGaP layer deposited on GaAs directly during epitaxial growth. PL line of the formed array of islands is in the range of 950–1000 nm at room temperature. Studies of PL in the temperature range 78–300 K indicate a significant inhomogeneity of the island array, the presence of nonradiative recombination centers, and carrier transport between islands. We observe in the photoluminescence excitation spectra a line associated with absorption in the residual two-dimensional InGaPAs layer. Annealing of the structures results in 300% increase of the PL intensity at room temperature with an insignificant short-wavelength shift of the island PL line, and also in improvement of the homogeneity within the island array.

The results of studying the optical properties of InGaAs quantum dots are presented. Single-layer InGaAs quantum dots with a height of 5.3, 3.6 and 2.6 monolayers, as well as three-stacked layers of tunnel-uncoupled quantum dots with a height of 2.6 monolayers were formed by molecular–beam epitaxy according to the Stransky-Krastanov mechanism on GaAs substrates, using the partial capping and annealing technique. A decrease in the size of quantum dots makes it possible to carry out a blueshift of the photoluminescence spectrum maximum from 1200 nm to 1090 nm, and an increase in the number of QD layers makes it possible to compensate for the decrease in the peak intensity. It is shown that this type of quantum dots is suitable for creating the lasers active regions with a vertical microcavity for neuromorphic computing.