An InAs/InGaAs quantum dot laser with a heterostructure epitaxially grown on a silicon substrate was used to fabricate injection microdisk lasers of different diameters (15–31 µm). A post-growth process includes photolithography and deep dry etching. No surface protection/passivation is applied. The microlasers are capable of operating heatsink-free in a continuous-wave regime at room and elevated temperatures. A record-low threshold current density of 0.36 kA/cm² was achieved in 31 µm diameter microdisks operating uncooled. In microlasers with a diameter of 15 µm, the minimum threshold current density was found to be 0.68 kA/cm². Thermal resistance of microdisk lasers monolithically grown on silicon agrees well with that of microdisks on GaAs substrates. The ageing test performed for microdisk lasers on silicon during 1000 h at a constant current revealed that the output power dropped by only ~9%. A preliminary estimate of the lifetime for quantum-dot (QD) microlasers on silicon (defined by a double drop of the power) is 83,000 h. Quantum dot microdisk lasers made of a heterostructure grown on GaAs were transferred onto a silicon wafer using indium bonding. Microlasers have a joint electrical contact over a residual n+ GaAs substrate, whereas their individual addressing is achieved by placing them down on a p-contact to separate contact pads. These microdisks hybridly integrated to silicon laser at room temperature in a continuous-wave mode. No effect of non-native substrate on device characteristics was found.

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.

We discuss the effect of self-heating on performance of injection microdisk lasers operating in continuous-wave (CW) regime at room and elevated temperature. A model is developed that allows one to obtain analytical expressions for the peak optical power limited by the thermal rollover effect, the corresponding injection current and excess temperature of the device. The model predicts, there exists the maximum temperature of microlaser operation in CW regime and the minimum mircrodisk diameter, at which CW lasing is possible. The model allows one to determine the dependence of the device characteristics on its diameter and the inherent parameters, such as thermal resistance, electrical resistance, non-radiative recombination and characteristic temperature of the threshold current. It is found that a rapid growth of the threshold current density with decreasing the diameter (which takes place even in the absence of the self-heating effect) is the main internal reason leading to the dependence of the temperature characteristics of the mirodisk laser on its size. In the calculations, we used a set of parameters extracted from experiments with InGaAs quantum dot microdisk lasers. The simulation results (in particular, the light-current curve and the dependence of the minimum microdisk diameter on ambient temperature) comply well with the measured dependences.

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.