It has been revealed that removing the shell of spontaneously formed InGaN nanowires increases the amplitude and narrows their emission spectrum. It has been established that radiative recombination dominates in the nanowires. And the dependence of the integrated photoluminescence intensity on the pump power for nanowires after etching is superlinear in comparison with the initial ones.

AlGaAs nanowires with InAs quantum dots on the silicon surface were synthesized by molecular-beam epitaxy. Morphological and optical properties of grown nanostructures were studied. It is important to note, that emission from quantum dots is observed in the wavelength range from 780 to 970 nm. Assumptions about the nature of short-wave radiation from quan-tum dots were formulated. In particular, one of the reasons may be the significant desorption of indium atoms and the presence of gallium atoms in the catalyst droplets during growth at the substrate temperature of 510 degrees C. Our work, therefore, opens new prospects for integration of direct bandgap semiconductors with silicon platform.

The influence of the growth time on the structural properties of InGaN nanowires grown on Si substrate by plasma-assisted molecular beam epitaxy are studied. Under appropriate other growth conditions, the growth for 2h leads to the formation of separated nanowires, whereas the growth for 2h 30min and 3h leads to the formation of nanostructures such as nano-umbrellas. The separated NWs exhibit a photoluminescence spectrum with maxima at about 590 nm, whereas the nano-umbrellas show two pronounced photoluminescence lines at 421 and 619 nm.

We demonstrate growth of AlGaAs NWs with GaAs QDs and InP NWs with InAsP QDs on silicon substrates. Results of GaAs QDs optical properties study have shown that these objects are sources of single photons. In case of InP NWs with InAsP QDs, the results showed that ~ 100% of homogeneously oriented NWs were formed with good optical quality of this system on a Si(111). PL spectrum peak near 1.3 μm indicates that such system is promising for optoelectronic devices.

The possibility of AlGaAs nanowires with GaAs quantum dots and InP nanowires with InAsP quantum dots growth by molecular-beam epitaxy on silicon substrates has been demonstrated. Results of GaAs quantum dots optical properties studies have shown that these objects are sources of single photons. In case of InP nanowires with InAsP quantum dots, the results we obtained indicate that nearly 100% of coherent nanowires can be formed with high optical quality of this system on a silicon surface. The presence of a band with maximum emission intensity near 1.3 μm makes it possible to consider the given system promising for further integration of optical elements on silicon platform with fiber-optic systems. Our work, therefore, opens new prospects for integration of direct bandgap semiconductors and singlephoton sources on silicon platform for various applications in the fields of silicon photonics and quantum information technology.

A possibility of the AlGaAs nanowires with multiply GaAs QDs MBE growth on silicon substrates has been demonstrated. The morphological on optical properties of grown structures were studied.

In this work, we present the results of photoluminescence measurements of wurtzite AlGaAs nanowires, coupled with the transmission electron microscopy structural analysis. AlGaAs NWs were grown by molecular beam epitaxy under the nominal aluminum content of 0.3 - 0.8. The results of TEM measurements demonstrated wurtzite crystal structure of AlGaAs nanowires.

We have studied the role of EL2 centers in formation of the photoelectric response of an array of radial n-type GaAs/AlxGa1 –xAs (x = 0.3) nanowires (NWs) grown by molecular beam epitaxy on a p-type silicon substrate. Results revealed a significant decrease in the time of NW photoresponse recovery as compared to that in a bulk crystal upon the transition of EL2 centers from a metastable nonactive state to the normal ground state.

The results of the investigations of photoluminescence and photoluminescence excitation spectra together with the transmission electron microscopy structural analysis of AlxGa1-xAs nanowires grown by molecular beam epitaxy with nominal aluminum content of 0.2 - 0.7 are presented. It is shown that the investigated nanowire possess wurtzite phase and the spectral positions of their luminescence band differ significantly from the bulk sphalerite type alloys of similar content.

Data on the growth and physical properties of nanostructures of the type “InAsP insert embedded in InP nanowire (NW)” grown on Si (111) surfaces by Au-assisted molecular-beam epitaxy are presented. It is found that nearly 100%-coherent NWs can be grown with a widely varying surface density. A relationship between the optical and structural properties of the NWs is revealed. It is shown that the NWs under study are formed of a purely wurtzite phase. The suggested technology opens up new opportunities for the integration of direct-gap III–V materials and silicon.

GaAs/AlGaAs heterostructure with 226 quantum cascades was synthesized by molecular-beam epitaxy. Structural and optical properties studies have shown high level of homogeneity and quality of epitaxial structure.

III–V nanowires, or a combination of the nanowires with quantum dots, are promising building blocks for future optoelectronic devices, in particular, single-photon emitters, lasers and photodetectors. In this work we present results of molecular beam epitaxial growth of combined nanostructures containing GaAs quantum dots inside AlGaAs nanowires on a silicon substrate showing a new way to combine quantum devices with Si technology.

We present the results of photoluminescence measurements of AlxGa1 – xAs nanowires, together with the transmission electron microscopy structural analysis. AlxGa1 – xAs nanowires were grown by molecular beam epitaxy under the nominal aluminum contents х = 0.3–0.7. The obtained results demonstrate the presence of wurtzite structure in AlxGa1 – xAs nanowires.

A theoretical and experimental description of the synthesis of GaP nanowire crystals by molecularbeam epitaxy on Si(111) substrates with the use of gold as a catalyst is presented. The ratio between the fluxes of materials to be deposited and the substrate temperature are varied for a short time during nanowire synthesis in order to analyze the possibility of producing nanoinclusions of different polytypes. It is established that variations in the ratio between the fluxes of materials to be deposited and in the growth temperature bring about the controllable formation of inclusions, among them are structurally cubic crystalline regions. The inclusions are several nanometers thick.

The emission directionality of self-catalytic GaAs nanowires in an AlGaAs shell, produced by molecular-beam epitaxy with a varied level of beryllium doping, is studied. It is shown that an undoped sample possesses pronounced waveguide properties along the growth direction. With increasing doping level, the intensity of the emission directed perpendicular to the lateral nanowire walls grows.

The data on the growth peculiarities and physical properties of GaAs insertions embedded in AlGaAs nanowires grown on Si (111) substrates by Au-assisted molecular beam epitaxy are presented. It is shown that by varying of the growth parameters it is possible to form structures like quantum dots emitting in a wide wavelengths range for both active and barrier parts. The technology proposed opens new possibilities for the integration of direct-band AIIIBV materials on silicon platform.

Efficient emission of THz radiation by AlGaAs nanowires via excitation of photocurrent by femtosecond optical pulses in nanowires was observed. Dynamics of photoinduced charge carrier was studied via influence of electron-hole plasma on THz radiation by optical pump THz probe method. It was found that characteristic time of screening of contact field is about 15 ps. Recombination of non-equilibrium occurs in two stages: fast recombination of free electron and holes (with relaxation time about 700 ps), and slow recombination (with relaxation time about 15 ns), which involves a capture of electrons and holes on the defects of crystalline structure of nanowires.

Arrays of (Ga,Mn)As crystal nanowires on a GaAs (100) substrate were obtained using molecular beam epitaxy at the substrate temperature 485 degrees C. From the high energy electron diffraction patterns, the crystallographic phase of the nanowires is detected to be cubic which is supporting by ex situ microscopy study.

The results obtained in a study of the structural and optical properties of GaAs/AlGaAs heterostructures with 228 quantum cascades, grown by molecular-beam epitaxy, and in a simulation of interband optical transitions and transitions between the energy levels of a cascade are presented.

It is shown that the atomic layer deposition of thin AlN layers can be used to passivate the surface states of GaAs nanowires synthesized by molecular-beam epitaxy. Studies of the optical properties of samples by low-temperature photoluminescence measurements shows that the photoluminescence-signal intensity can be increased by a factor of up to five by passivating the nanowires with a 25-Å-thick AlN layer.