Svetlana A. Kadinskaya

A CsPbBr ₃ -coated ZnO microprism supports robust whispering gallery lasing near 537 nm with a Q -factor above 10 ³ via a decoupled cavity design.

In this manuscript, we present a study on the optical properties of ZnO NWs and microcrystals synthesized via hydrothermal method. The NWs were characterized by low-temperature photoluminescence spectroscopy, which revealed resonance modes indicating random lasing behavior mediated by scattering from misoriented nanowires. The spectral position of the resonance modes suggests lasing in the P-band region of exciton–exciton interaction. Our results also indicate a correlation between the surface density of nanostructures and the peak emission intensity. In addition, optically behavior of individual ZnO microprisms integrated in with a thin perovskite active layer were investigated by room-temperature microphotoluminescence spectroscopy. The results indicate that the ZnO microprisms are efficient optical cavities. Overall, our findings demonstrate the potential of hydrothermal synthesis for the fabrication of efficient ZnO-based light-emitting devices.

Emerging technologies for integrated optical circuits demand novel approaches and materials. This includes a search for nanoscale waveguides that should satisfy criteria of high optical density, small cross‐section, technological feasibility and structural perfection. All these criteria are met with self‐assembled gallium phosphide (GaP) epitaxial nanowires. In this work, the effects of the nanowire geometry on their waveguiding properties are studied both experimentally and numerically. Cut‐off wavelength dependence on the nanowire diameter is analyzed to demonstrate the pathways for fabrication of low‐loss and subwavelength cross‐section waveguides for visible and near‐infrared (IR) ranges. Probing the waveguides with a supercontinuum laser unveils the filtering properties of the nanowires due to their resonant action. The nanowires exhibit perfect elasticity allowing fabrication of curved waveguides. It is demonstrated that for the nanowire diameters exceeding the cut‐off value, the bending does not sufficiently reduce the field confinement promoting applicability of the approach for the development of nanoscale waveguides with a preassigned geometry. Optical X‐coupler made of two GaP nanowires allowing for spectral separation of the signal is fabricated. The results of this work open new ways for the utilization of GaP nanowires as elements of advanced photonic logic circuits and nanoscale interferometers.

Zinc oxide (ZnO) nanostructures are widely used in various fields of science and technology due to their properties and ease of fabrication. To achieve the desired characteristics for subsequent device application, it is necessary to develop growth methods allowing for control over the nanostructures’ morphology and crystallinity governing their optical and electronic properties. In this work, we grow ZnO nanostructures via hydrothermal synthesis using surfactants that significantly affect the growth kinetics. Nanostructures with geometry from nanowires to hexapods are obtained and studied with photoluminescence (PL) spectroscopy. Analysis of the photoluminescence spectra demonstrates pronounced exciton on a neutral donor UV emission in all of the samples. Changing the growth medium chemical composition affects the emission characteristics sufficiently. Apart the UV emission, nanostructures synthesized without the surfactants demonstrate deep-level emission in the visible range with a peak near 620 nm. Structures synthesized with the use of sodium citrate exhibit emission peak near 520 nm, and those with polyethylenimine do not exhibit the deep-level emission. Thus, we demonstrate the correlation between the hydrothermal growth conditions and the obtained ZnO nanostructures’ optical properties, opening up new possibilities for their precise control and application in nanophotonics, UV–Vis and white light sources.

The development of novel nanophotonic devices and circuits necessitates studies of optical phenomena in nanoscale structures. Catalyzed semiconductor nanowires are known for their unique properties including high crystallinity and silicon compatibility making them the perfect platform for optoelectronics and nanophotonics. In this work, we explore numerically optical properties of gallium phosphide nanowires governed by their dimensions and study waveguiding, coupling between the two wires and resonant field confinement to unveil nanoscale phenomena paving the way for the fabrication of the integrated optical circuits. Photonic coupling between the two adjacent nanowires is studied in detail to demonstrate good tolerance of the coupling to the distance between the two aligned wires providing losses not exceeding 30% for the gap of 100 nm. The dependence of this coupling is investigated with the wires placed nearby varying their relative position. It is found that due to the resonant properties of a nanowire acting as a Fabry–Perot cavity, two coupled wires represent an attractive system for control over the optical signal processing governed by the signal interference. We explore size-dependent plasmonic behaviors of the metallic Ga nanoparticle enabling GaP nanowire as an antenna-waveguide hybrid system. We demonstrate numerically that variation of the structure dimensions allows the nearfield tailoring. As such, we explore GaP NWs as a versatile platform for integrated photonic circuits.

Currently, new nanostructured materials based on composite metal oxides is of great interest for the development of gas sensors with improved functional characteristics. In this work, zinc oxide nanowires were synthesized by hydrothermal method. Hierarchical ZnO/ZnFe₂O₄ nanostructures were obtained by immersion of zinc oxide layers in ferrous sulphate aqueous solution. The mechanism of zinc ferrite formation during the interaction of zinc oxide with iron sulphate is considered. The crystal structure of ZnO and ZnO/ZnFe₂O₄ were studied by Raman spectroscopy. The sensitivity of ZnO and ZnO/ZnFe₂O₄ nanostructures to isopropyl alcohol vapors was analyzed. It was shown that there is an optimal concentration of ferrous sulphate used to modify zinc oxide nanowires and synthesize ZnO/ZnFe₂O₄ composite nanostructures.

In this work we study zinc oxide nanostructures of various geometries synthesized via the hydrothermal technique on Si (111) substrate. We demonstrate capabilities of the growth protocol for control over the morphology of nanostructures varying from nanowires to hexapods. The obtained samples were studied by photoluminescence spectroscopy to demonstrate a very narrow spontaneous emission near 370 nm. Despite cheap and feasible fabrication, the obtained nanostructures possess high crystallinity confirmed by the absence of typical for ZnO wide emission band in the visible region, related with the structure imperfections. This property together with the capabilities of the geometrical control over the nanostructures unveil perspectives of the reported approach for future UV photonic applications.

In this work we study zinc oxide nanostructures of various geometries synthesized via hydrothermal technique on Si (111) substrate. We demonstrate capabilities of the growth protocol for control over the nanostructures morphology varying from nanowires to hexapods. The obtained samples are studied by photoluminescence spectroscopy to demonstrate a very narrow spontaneous emission band near 370 nm. Despite cheap and feasible fabrication, the obtained nanostructures possess high crystallinity confirmed by the absence of typical for ZnO wide emission band in the visible region related with the structure imperfections. This property together with the capabilities of the geometrical control over the nanostructures unveil perspectives of the reported approach for future UV photonic applications.

We present an analysis of spectral and threshold characteristics of InGaAs/GaAs quantum well-dot microdisk laser operated under cw current injection at room temperature without external cooling. The experimental values of the threshold current for the disk and ring microlasers are compared. We observe that the threshold current can be significantly decreased in devices with large diameters (more than 30 μm) by using the ring geometry.