Many groups rely on growth on vicinal substrates and step-bunching effect at the upper interface of the growing InGaAs layer. For instance, the initial stage of InGaAs growth by MOVPE on multiatomic-stepped GaAs structures was studied in [22]. It was found that in the initial stages of InGaAs growth, Ga and In atoms preferentially attach themselves to the bottom edges of the multiatomic steps. The key issues in the formation of InGaAs QWRs are the uniformity of the multiatomic steps and the large modulation in the lateral thickness of InGaAs on multiatomic-stepped GaAs structures. As early as in 1997, it was demonstrated that the luminescence peak position strongly depends upon growth parameters and can be tuned in a wide spectral interval even for the same \(x\) and average thickness of the deposited InGaAs [31]. The samples were grown by submonolayer deposition of InAs and GaAs by MBE and had nominally the same composition (\(\sim\)31%) and thickness (\(\sim\)7 nm). However, for the sample grown in the alternating mode of group III and group V atoms, the maximum of PL emission was shifted by 120 meV towards lower energies with respect to the emission from the first sample grown in the continuous deposition mode. In reference [30], the impact of substrate misorientation and the number of deposited In\({}_{0.18}\)Ga\({}_{0.82}\)As layers on strain relaxation mechanisms were studied. Multiple In\({}_{0.18}\)Ga\({}_{0.82}\)As/GaAs layers were deposited by MBE on exactly oriented substrates as well as on 2\({}^{\circ}\) misoriented towards the [0-11] direction GaAs substrates. In the case of the growth on nominal GaAs(100) surfaces, the strain relaxation was governed by dislocation formation. In contrast, the additional strain relaxation mechanism was revealed for vicinal GaAs(100) substrates. If the number of deposited In\({}_{0.18}\)Ga\({}_{0.82}\)As layers is less than 8, step bunching provided a mechanism for strain relaxation. In case the number of In\({}_{0.18}\)Ga\({}_{0.82}\)As layers exceeds 10, bunched corners along with two [051] and [0; 1; 2; 3; 4; 5] directions also contribute to the strain relaxation in addition to the step bunching. Morphology of the strained In\({}_{0.3}\)Ga\({}_{0.7}\)As (2-4 nm)/GaAs (2.7 nm)/GaAs\({}_{0.6}\)P\({}_{0.4}\) (3 nm)/GaAs (2.7 nm) superlattices deposited on GaAs surfaces with different misorientations (0 and 6\({}^{\circ}\) off) was investigated in [19; 25; 26]. For both types of substrates, growth conditions were exactly the same. A significant layer undulation was observed in the case of a 6\({}^{\circ}\) misoriented substrate. This corrugation was attributed to step bunching and non-uniform precursor incorporation between steps and terraces. In contrast, the growth of the exactly oriented substrate resulted in flat morphology. The undulation effect was the most pronounced for InGaAs layers. As a result, a periodic array of InGaAs nanowires on planar wells was formed that was referred to as Wires-on-Well (WoW). Lateral periodicity of layer undulation was determined by TEM as 66 nm. The total height of the WoW was \(\sim\)3.1 nm, and the minimum thickness of the InGaAs, at the boundary between one wire and the next one was \(\sim\)0.71 nm. The wire width was about 48.6 nm. The WoW geometry can be tuned by changing equivalent thicknesses of InGaAs and GaAsP layers. An increase in the equivalent thickness of InGaAs results in the enhancement of the height of the wires. The wire width also increased with the InGaAs equivalent thickness, but this effect is less pronounced. Strain-balancing was crucial to maintain the periodicity of the InGaAs WoW array. The WoW photoluminescence peak shifted according to the size of InGaAs wires in optical region 1.15-1.3 eV, and the intensity was affected by the accumulation of lattice-mismatch stress. In reference [20], the authors reported on nanostructures that they referred to as QWRs.