The direct integration of epitaxial III-V and III-N heterostructures on Si substrates is a promising platform for the development of optoelectronic devices. Nanowires, due to their unique geometry, allow for the direct synthesis of semiconductor light-emitting diodes (LED) on crystalline lattice-mismatched Si wafers. Here, we present molecular beam epitaxy of regular arrays n-GaN/i-InGaN/p-GaN heterostructured nanowires and tripods on Si/SiO₂ substrates prepatterned with the use of cost-effective and rapid microsphere optical lithography. This approach provides the selective-area synthesis of the ordered nanowire arrays on large-area Si substrates. We experimentally show that the n-GaN NWs/n-Si interface demonstrates rectifying behavior and the fabricated n-GaN/i-InGaN/p-GaN NWs-based LEDs have electroluminescence in the broad spectral range, with a maximum near 500 nm, which can be employed for multicolor or white light screen development.

Technological progress makes it possible to significantly reduce the size of semiconductor laser emitters to microscales and sizes commensurate with the emission wavelength. Extreme laser miniaturization can be achieved using disk or ring resonators supporting high-Q whispering gallery modes (WGM). WGM lasers are interesting not only due to small sizes (small mode volume) but also for their long times of light-matter interaction, unique capabilities of sensing and studying of quantum chaos and so on. On the other hand, small losses for the output of emission in high-Q resonators can negate the practical benefits of the laser or even completely hide the peculiarities of the light physics inside the cavity. In this review, we attempted to summarize the published data on the achieved optical output power in different III-V injection microlasers and analyzed the key characteristics that limit the maximum output power, especially influence of the active region self-heating at cw operation and impeded light extraction out of WGM cavities. We compared various III-V materials and fabrication methods developed for improving emission output. We also observe very low relative intensity noise in microdisk lasers and harmonics of the resonance frequency in the relative intensity noise spectrum.

Microlasers supporting whispering gallery modes attract great interest due to their potential use in photonic integrated circuits, as they have a size just an order of magnitude larger than their emission wavelength and exhibit good thermal and dynamic properties. It is usually assumed that in disk microlasers, a whispering gallery mode of the highest azimuthal order and first radial order is the lasing one. However, in this work, we argue that it is of much lower azimuthal order and much higher radial order. We provide both experimental evidence in the form of far-field radiation patterns measured for disk microlasers with 10, 15, and 25 μm radii and theoretical analysis of the modal gain. We investigate how surface recombination of carriers leads to depletion of the outer region of the disk and, thus, to lowering of the gain. This leads to a preference for higher radial order modes. At the same time, modes that are localized too close to the center have smaller vertical confinement factors, which we prove with numerical modeling showing increased leakage of the mode's electric field to the substrate. When both aforementioned factors are considered, we arrive at an estimation of the radial and azimuthal mode order that agrees with the experiment.

Spectral characteristics of quantum dot (QD) microdisk lasers under spatially inhomogeneous optical excitation are investigated. By varying the position and size of the continuous-wave excitation spot over the laser cavity, we demonstrate controllable selection and switching of lasing whispering gallery modes (WGMs) at room temperature. Experimental results show that shifting the excitation spot across the surface of 10 μm microdisk laser enables reversible wavelength switching between WGMs at 1285 nm and 1313 nm, corresponding to different radial mode orders. Theoretical modeling and near-field scanning optical microscopy confirm that the observed spectral switching of lasing WGM is caused by spatially selective charge carrier distribution arising from the suppressed lateral transport of charge carriers in quantum dot active region. The findings highlight the potential for actively spectral switchable microlasers for applications in photonic integration and optical sensing.

We investigated the dependence of the spectral position of the lasing line of a microdisk laser with InAs/InGaAs/GaAs quantum dots on the refractive index of an aqueous solution in which the microlaser is immersed. For microlasers with 10 μm diameter immersed in an aqueous solution of glucose, the maximum resonance shift of 9.4 nm/RIU was obtained.

We study photoluminescence of InP/InAsP/InP nanostructures monolithically integrated to a Si(100) substrate. The InP/InAsP/InP nanostructures were grown in pre-formed pits in the silicon substrate using an original approach based on selective area growth and driven by a molten alloy in metal–organic vapor epitaxy method. This approach provides the selective-area synthesis of the ordered emitters arrays on Si substrates. The obtained InP/InAsP/InP nanostructures have a submicron size. The individual InP/InAsP/InP nanostructures were investigated by photoluminescence spectroscopy at room temperature. The tuning of the emission line in the spectral range from 1200 nm to 1550 nm was obtained depending on the growth parameters. These results provide a path for the growth on Si(100) substrate of position-controlled heterojunctions based on InAs_1−xP_x for nanoscale optical devices operating at the telecom band.