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The authors at ANU were supported by the Australian Research Council. The authors at DSI were supported by DSI core funds and A*STAR SERC Pharos program, Grant 152 73 00025 (Singapore).

Nanomechanical oscillators based on amorphous carbon whiskers, localized on the top of tungsten tip were fabricated and investigated. The whiskers were grown in the scanning electron microscope chamber using focused electron beam technique. Oscillation trajectories and amplitude-frequency characteristic of the oscillator were visualized at low and ambient pressure using a scanning electron microscope and a confocal laser-scanning microscope, respectively. We experimentally show that at ambient pressure, the resonant frequency decreases significantly but the Q-factor of the oscillator unexpectedly increases with respect to experimental data acquired at low pressure. The explanation was provided taking into account the role of thin water layer absorbed on the whisker from atmosphere. The model of the coupled oscillators is considered.

This work is aimed at finding and developing new ways to improve and optimize the characteristics of transparent conductive electrodes based on SWCNT by forming a texture in a continuous layer by combination of lithography and oxygen plasma treatment. A theoretical and an experimental justification for choosing thickness of a textured pattern, together with the experimental results of optical and electrophysical measurements were presented. The resistance of the textured electrode was 187.5 Ohm/sq, which is 17.5% lower than resistance of the electrode made from a continuous SWCNT layer with a same transparency of 95%. An analytical calculation showed that the use of extremely absorbing SWCNT films for texturing allows to obtain ∼ 54% gain in the resistance of a textured electrode compared to a continuous SWCNT’s layer.

Strain-induced effects on the optical properties of GaP nanowires (NWs) were investigated with micro-Raman mapping and numerical calculations. Various techniques for achieving high mechanical strains in NWs were studied including NW fixation with metallic contacts created with optical lithography and AFM-based nanomanipulations. Polarization-dependent micro-Raman mapping of highly-strained GaP NW was carried out. The impact of tension and compression strains on the Raman signal of bent NW was separated. Numerical model describing strain-induced behavior of TO Raman mode was introduced.

This study is devoted to the investigation of the optical properties and composition of GaPN/GaP nanowire heterostructure. Nanowire arrays were grown on Si substrate (111) by the plasma-assisted molecular beam epitaxy. Polydimethylsiloxane membrane encapsulation was used to obtain the free-standing NW arrays. The morphology of GaPN/GaP NW was investigated with scanning electron microscopy. The optical properties of the GaPN nanowire arrays were determined at the He temperature (5K) with photoluminescence spectroscopy. Analysis of photoluminescence response allowed us to conclude that the incorporation of nitrogen atoms during the growth occurs both in the nanowires and in the parasitic islands with different content. Direct bandgap-like behaviour of the GaPN/GaP nanowires demonstrates the potential of nanowire-polymer matrix practical application in future optoelectronic devices.

Numerical modelling of Schottky diode formed by single GaN nanowire on Si substrate was performed. Two metals, namely, gold and platinum forming the Schottky barrier were considered. The potential barrier height was calculated taking into account occurrence of image force as well as Fermi level pinning at metal/semiconductor interface. Volt-ampere characteristics were obtained for different NW doping levels considering Wentzel–Kramers–Brillouin tunneling model. Cutoff frequencies are evaluated from current-time relaxation curves for different NW lengths and doping levels. It is shown that such diode structure demonstrates high-speed performance with cutoff frequency in the range from 0.1 to 0.9 THz for both studied metals.

This work proposes new chemical and mechanical materials and techniques for III-V semiconductor NW/silicone membrane formation and optoelectronic device fabrication. Molecular beam epitaxy (MBE)-synthesized n-, p- and i-GaP NWs were encapsulated by introduced G-coating method into synthesized polydimethylsiloxane- graft -polystyrene and released from the Si growth substrate. The fabricated membranes were contacted with different materials including single-walled carbon nanotubes or ferrocenyl-containing polymethylhydrosiloxane with and without multi-walled carbon nanotubes doping. The electrical connection of the fabricated membranes was verified by electron beam induced current (EBIC) spectroscopy. The developed methods and materials can be applied for fabrication of high quality flexible inorganic optoelectronic devices.

Meta-optics based on optically-resonant dielectric nanostructures is a rapidly developing research field with many potential applications. Halide perovskite metasurfaces emerged recently as a novel platform for meta-optics, and they offer unique opportunities for control of light in optoelectronic devices. Here we employ the generalized Kerker conditions to overlap electric and magnetic Mie resonances in each meta-atom of MAPbBr3 perovskite metasurface and demonstrate broadband suppression of reflection down to 4%. We reveal also that metasurface nanostructuring is also beneficial for the enhancement of photoluminescence. Our results may be useful for applications of nanostructured halide perovskites in photovoltaics and semi-transparent multifunctional metadevices where reflection reduction is important for their high efficiency.

Spin-wave bandpass filters with small sizes on the basis of thin Y 3 Fe 5 O 12 [yttrium-iron garnet (YIG)] films on Gd 3 Ga 5 O 12 [gadolinium-gallium garnet (GGG)] and SiO 2 / Si substrates have been constructed. A thin YIG film with a thickness of 0.8 μ m on SiO 2 / Si substrates has been grown by the ion-beam sputtering. It is found that the coplanar antenna structure can be successfully used to construct tunable small-sized narrowband bandpass filters based on spin waves. The filter transmission characteristic has a nonreciprocity when the direction of energy propagation changes. Spin-wave filter characteristics are analyzed using the transmission-matrix formalism.

The effect of hydrogen plasma treatment on the electrical and optical properties of GaN NWs/Si based vertical hetero structures synthesized by the method of plasma molecular beam epitaxy is studied. The effect of treatment has been carefully studied by variation of the passivation duration. Measurements of the electron beam-induced current (EBIC) technique showed the absence of potential barriers between the active parts of the diode and the contacts, which indicates the ohmic behavior of the latter. The current - voltage characteristics show that hydrogen can efficiently passivate recombination centers at the GaN NWs/Si heterointerface. It is established that the optimal passivation duration, providing improved electrical properties, is 10 minutes in the adopted passivation modes. It is shown that a longer treatment causes a deterioration in electrical properties.

The nanomechanical oscillators (NMO) in the form of carbon nanowhiskers (CNW) with oval cross-sections have been created and studied in scanning-electron microscope (SEM). For measurement of amplitude-frequency characteristics of CNWs the methods of machine vision were used. The CNWs and 2D framework carbon nanostructures were grown on tops of W needles with various radius of curvature in the range of (100-350) nm. Resonant oscillations along the big and the small sizes of CNW cross-section and rotational resonant modes of NMO were observed and analyzed.The nanomechanical oscillators (NMO) in the form of carbon nanowhiskers (CNW) with oval cross-sections have been created and studied in scanning-electron microscope (SEM). For measurement of amplitude-frequency characteristics of CNWs the methods of machine vision were used. The CNWs and 2D framework carbon nanostructures were grown on tops of W needles with various radius of curvature in the range of (100-350) nm. Resonant oscillations along the big and the small sizes of CNW cross-section and rotational resonant modes of NMO were observed and analyzed.

We present an unstable ring optical cavity with disk active element and multipass system. The modeling shows that unstable cavities are preferable for lasers with large fundamental mode size. Lasing with different magnification is demonstrated, the best beam quality is M2=2.5.

Revealing hidden non-radiative (dark) of resonant nanostructures using optical methods such as dark-field spectroscopy often becomes a sophisticated problem due to a weak coupling of these modes with a far-field radiation, whereas methods of dark-modes spectroscopy, e.g. cathodoluminescence or elastic energy losses, are not always convenient in use. Here, we suggest an approach for experimental determining the mode structure of a nanoresonator basing on utilizing intrinsic incoherent Raman scattering. We theoretically predict the efficiency of this approach and realize it experimentally for silicon nanoparticle resonators possessing strong Raman line at 520 cm^-1. With this method, we studied a silicon nanoparticle placed on a gold substrate and reveal the spectral position of a low-radiative magnetic quadrupole mode which is hardly observable with common dark-field optical spectroscopy.

Optical tweezers are widely used for manipulating nano- and micro sized particles. The presence of a special plasmon substrate can significantly affect the optical forces acting on an object. This paper discusses the possibility of experimental measuring optical plasmon forces using a mechanical resonator based on a carbon nanowhisker. A mathematical model describing the effect of optical forces on nanowhisker oscillations with an additional nanoparticle at the end is presented with taking into account the effect of surface plasmon waves on the substrate.

Formation and propagation of the antiphase domains in dilute nitride GaPN/GaP epitaxial heterostructures grown on Si (001) by plasma assisted molecular beam epitaxy (PA-MBE) on silicon is studied. Role of the layer composition, substrate orientation and growth conditions are discussed. Composition of the dilute nitride film was studied by X-ray diffraction (XRD) while the effect of the antiphase disorder in GaP buffer layer on GaPN epilayer structural properties was studied by transmission electron (TEM) and scanning electron microscopy (SEM). Controllable transition between antiphase disordered and monodomain film depending on the concentration of incorporated nitrogen is demonstrated – transition to the monodomain film occurs in dilute nitride GaPN layers starting low with 0.4% of incorporated nitrogen. Control of the antiphase disorder allows to tune mean film polarity and second order nonlinear optical response of III-phosphide heterostructures.

This work is devoted to fabrication and characterization of a GaAs solar cell with a CNT top contact. The characteristics of a conventional solar cell with a metal contact grid and a solar cell with a CNT electrode were compared to demonstrate the benefits of a CNT based approach. The photoelectric properties of the solar cells were studied by measuring the IV characteristics and external quantum efficiency. The fabricated CNT solar cell showed better performance due to improved photocurrent collection efficiency. The demonstrated technology for the fabrication of CNT electrodes can be applied to a wide range of semiconductor photovoltaic devices, including flexible thin-film solar cells and solar cells based on nanowires.

Gallium phosphide is an important material in terms of III-V semiconductors integration on Si. In this work we study photovoltaic properties of GaP:Be/GaNP (Eg ~ 2.0eV)/GaP:Si p-i-n heterostructure grown on Si (100) with GaP buffer by plasma-assisted molecular beam epitaxy. Correlation between the structural and optoelectronic properties of the fabricated device was studied by scanning and transmission electron microscopy (TEM), electron beam induced current (EBIC) and deep-level transient spectroscopy (DLTS) techniques. The I–V characteristic of the fabricated mesa diode demonstrates short circuit current of 2.2 mA/cm2 and open circuit voltage of 0.8 V. TEM studies of the epilayer structural properties demonstrate high density of antiphase domains in the n-doped GaP buffer layer; however, they found to be annihilated in dilute nitride layer, where mainly threading dislocations were formed. EBIC investigation shows that crystalline imperfections of the heterostructure leads to poor carriers transport affecting the energy conversion efficiency. We performed numerical modeling concerning presence of the structural defects and discuss their influence on the diode performance. The carried out study is the initial step on the way to development of the growth technique of the GaP-based dilute nitride direct bandgap materials on Si for photonic and photovoltaic applications.

The concept of a high-power thin-rod Yb:YAG laser amplifier with high-brightness diode pumping was proposed. The principle of the amplifier parameter variation aimed at achieving an efficient signal gain at different power levels was developed. Three versions of thin-rod gain modules were implemented, where small and strong signal gains were studied experimentally. The ultrafast laser system with high average power (28 W) and high pulse energy (2.5 mJ) was created on the basis of the unique thin-rod gain modules.

Hybrid Yb:Y 2 O 3 ceramic thin-rod femtosecond amplifier is reported. By 4-pass amplification scheme, output power of 1.4 W with gain of 14 is achieved from 100 mW, 1033 nm, 30 MHz fiber seeder. The extracted gain spectrum shows gain bandwidth of about 5.0 nm centered at 1030.6 nm.

We show that the rate of stimulated emission by electron, passing through nanoscale constriction, can beenhanced substantially (by several orders) with proper tailoring of the constriction shape.

Structural and emission properties of few-electron In(Ga)P/GaInP quantum dots (QDs) representing natural Wigner molecules (WM) and whispering gallery mode (WGM) electron ($e$) cavities have been investigated. QD structures were grown using self-organized metal-organic vapor phase epitaxy and deposition from $\ensuremath{\sim}3$ to 7 monolayers of InP at $700{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$. Using atomic force microscopy, transmission electron microscopy, near-field scanning optical microscopy (NSOM), and $\ensuremath{\mu}$-photoluminescence ($\ensuremath{\mu}$-PL) spectra we obtained In(Ga)P/GaInP QDs having lateral size 80--180 nm, height 5--30 nm, Ga content 0.0--0.4, density $2\ensuremath{-}10\phantom{\rule{0.16em}{0ex}}\ensuremath{\mu}{\mathrm{m}}^{\ensuremath{-}2}$, and electron population up to 20 and demonstrated control of their density and size distribution. Using high-spatial-resolution low-temperature PL spectra, NSOM imaging, and calculations of charge density distributions we observed Wigner localization and $e$-cavity effects for a series of dots having quantum confinement $\ensuremath{\hbar}{\ensuremath{\omega}}_{0}=0.5\ensuremath{-}6\phantom{\rule{0.16em}{0ex}}\mathrm{meV}$. We used these data together with time-resolved PL measurements to clarify the effect of Coulomb interaction and WM formation on emission spectra of few-electron QDs. We present direct observation of $2e$, $6e$, and $9e$ WMs; $2e$ and $4e$ WGMs; and Fabry-Perot $e$ modes and establish conditions of $e$-WGM-cavity formation in these QDs.

International audience; Low-temperature plasma enhanced atomic layer deposition (PE-ALD) was successfully used to grow silicon (Si) doped amorphous and microcrystalline gallium phosphide (GaP) layers onto p-type Si wafers for the fabrication of n-GaP/p-Si heterojunction solar cells. PE-ALD was realized at 380 °C with continuous H2 plasma discharge and the alternate use of phosphine and trimethylgallium as sources of P and Ga atoms, respectively. The layers were doped with silicon thanks to silane (SiH4) diluted in H2 that was introduced as a separated step. High SiH4 dilution in H2 (0.1%) allows us to deposit stoichiometric GaP layers. Hall measurements performed on the GaP:Si/p-Si structures reveal the presence of an n-type layer with a sheet electron density of 6–10 × 1013 cm−2 and an electron mobility of 13–25 cm2 V−1 s−1 at 300 K. This is associated with the formation of a strong inversion layer in the p-Si substrate due to strong band bending at the GaP/Si interface. GaP:Si/p-Si heterostructures exhibit a clear photovoltaic effect, with the performance being currently limited by the poor quality of the p-Si wafers and reflection losses at the GaP surface. This opens interesting perspectives for Si doped GaP deposited by PE-ALD for the fabrication of p-Si based heterojunction solar cells.

Dewetting of thin metal films is one of the most widespread method for functional plasmonic nanostructures fabrication. However, simple thermal-induced dewetting does not allow to control degree of nanostructures order without additional lithographic process steps. Here we propose a novel method for lithography-free and large-scale fabrication of plasmonic nanostructures via controllable femtosecond laser-induced dewetting. The method is based on femtosecond laser surface pattering of a thin film followed by a nanoscale hydrodynamical instability, which is found to be very controllable under specific irradiation conditions. We achieve control over degree of nanostructures order by changing laser irradiation parametrs and film thickness. This allowed us to exploit the method for the broad range of applications: resonant light absorbtion and scattering, sensing, and potential improving of thin-film solar cells.

Enhancement of optical response with high-index dielectric nanoparticles is attributed to the excitation of their Mie-type magnetic and electric resonances. Here we study Raman scattering from crystalline silicon nanoparticles and reveal that magnetic dipole modes have a much stronger effect on the scattering than electric modes of the same order. We demonstrate experimentally a 140-fold enhancement of the Raman signal from individual silicon spherical nanoparticles at the magnetic dipole resonance. Our results confirm the importance of the optically-induced magnetic response of subwavelength dielectric nanoparticles for enhancing light-matter interactions.

Design and operation modes of double-junction monolithic lattice-matched solar cells based on the ZnSiP2/Si system of materials have been calculated. The effect of the photoactive region thickness and minority carrier lifetime in ZnSiP2 layers on the efficiency of conversion of the incident solar light energy into electrical power was determined. It is shown that solar cells based on ZnSiP2/Si heterostructures can provide efficiencies of 28.8% at AM1.5D, 100 mW/cm2, and 33.3% at AM1.5D, 200 W/cm2.

We experimentally investigated the role of background signal in time resolved photoluminescence experiments with single quantum dots on substrates. We show that the background fluorescence signal from thin gold films fabricated by electron-beam evaporation and from Al2O3 layers fabricated by atomic layer deposition have to be taken into consideration in experiments on the single photon level. Though all investigated components can be distinguished by their photoluminescence decay rates, the presence of the background signal prevents the observation of photon antibunching from single quantum dots. Moreover, a single quantum dot acts as a hot spot enabling the plasmon supported fluorescence enhancement of gold.

We compare the spatial resolution and image contrast of an erythrocyte surface obtained by means of scanning force microscopy (SFM) with conventional hydrophobic Si probes and probes modified by hydrophilic Pt/C whisker probes. It is shown that probes with Pt/C nanowhiskers provide a higher spatial resolution and contrast when imaging relief on the surface of erythrocytes. The contrast inversion is revealed in some areas of the SFM images when replacing Si probes by probes with Pt/C nanowhiskers. The origin of this inversion in the tapping and contact modes is discussed.

High-power picosecond laser for OPCPA pumping is under development. It is composed of ytterbium fiber oscillator, Yb:YAG thin-rod preamplifiers and Yb:YAG thin-disk amplifier. 120W average power, 10mJ pulse energy with diffraction-limited beam quality is achieved.

We present a synthesis method to fabricate framed carbon-based nanostructures having highly anisotropic shapes, in particular, the nanofork and nanoscalpel structures which are obtained systematically under optimized growth conditions. A theoretical model is developed to explain the formation of such nanostructures on Si cantilevers and W etched wires exposed to a focused electron beam. We then demonstrate the potentials of these nanostructures as functional tips for scanning probe microscopy. Owing to their anisotropic shapes, such tips can be very useful for nanolithography, nanosurgery of biological objects, and precise manipulation with surface particles. Overall, our method provides a simple and robust way to produce functional scanning probe microscopy tips with variable shapes and enhanced capabilities for different applications compared to standard cantilevers.

Achieving efficient localization of white light at the nanoscale is a major challenge due to the diffraction limit, and nanoscale emitters generating light with a broadband spectrum require complicated engineering. Here we suggest a simple, yet highly efficient, nanoscale white-light source based on a hybrid Si/Au nanoparticle with ultrabroadband (1.3–3.4 eV) spectral characteristics. We incorporate this novel source into a scanning-probe microscope and observe broadband spectrum of photoluminescence that allows fast mapping of local optical response of advanced nanophotonic structures with submicron resolution, thus realizing ultrabroadband near-field nanospectroscopy.

Microdisk lasers based on three InGaAsN/GaAs quantum wells with different types of surface passivation are fabricated and studied under optical pumping. Room temperature lasing at 1.3 μm in 7 μm in diameter microdisks with InGaAsN/GaAs QW is demonstrated. We evaluated the thermal resistance as 1 °C/mW. publishedVersion

Change the shape and size of materials supports new functionalities never found in the sources. This strategy has been recently applied for porous crystalline materials - metal-organic frameworks (MOFs) to create hollow nanoscale structures or mesostructures with improved functional properties. However, such structures are characterized by amorphous state or polycrystallinity which limits their applicability. Here we follow this strategy to create such nano- and mesostructures with perfect crystallinity and new photonics functionalities by laser or focused ion beam fabrication.

Nanoparticle oligomers made of metallic and/or dielectric nanoparticles are able to support sharp Fano resonances originating from an interference of two resonant modes with different spectral width. For practical applications, it is necessary to have an approach for tuning the Fano resonances of a nanostructure after its fabrication. Herein, we demonstrate a novel type of reconfigurable hybrid metaldielectric (Au-Si) oligomers supporting fine-tunable magnetic Fano resonances. We present an expanded experimental results of the Fano resonance tailoring via femtosecond laser melting of the plasmonic parts at the nanoscale. We believe that our findings pave the way to realization of nanophotonic elements that can be adjusted after their manufacturing.

The development of multifunctional systems for investigation of different parameters involved in chemical reactions is a vital problem in case of low concentrations of tested matter. Here, we investigate hybrid plasmonic-dielectric system and demonstrate possibility of such application for multifunctional sensing.

Electrically Driven Optical Antennas represent promising issues for integrated plasmonic nanosources. However, their low quantum efficiency (QE) remains a major hurdle. To address this issue, we analyze the different light emission mechanisms in planar nanoscale devices. We found that the electrical properties of the device are dictating the processes at play. For low device conductance, photons are essentially emitted by inelastic tunneling events and the applied voltage sets the highest photon energy. For high conductance gap antennas, we show that the spectrum released by the device originates from the spontaneous emission of out-of-equilibrium electronic distribution. We then propose a novel route for increasing the QE. Estimation shows that if the nanoantennas are excited by electrons passing ballistically through mesoscopic contacts constituting the antenna, the excitation QE may reach ∼ 0.01–0.1. Finally, we explore an alternative approach based on charge injection in semiconductor Mie resonators.

We analyze the optical forces acting on a nanoparticle placed in the vicinity of a plasmonic interface. We show that the under oblique plane wave excitation the nanoparticle excites surface plasmon polariton propagating along the plasmonic interface. The momentum conservation law in the plane of the interface results in appearance of optical recoil force attracting the particle to the source of light. The analyzed recoil force could increase the radiation pressure force by an order of magnitude.

We perform the extraction of the surface local diagonal conductivity tensor of fabricated metasurface consisting of gold ellipsoidal nanodisks. We present the procedure of effective conductivity retrieving as a combination of theoretical and experimental methods. Finally, we analyze the conductivity tensor obtained.

Composite active elements (AEs) of thin-disk geometry with an anti-amplified-spontaneous-emission (ASE) cap were created for the first time from dissimilar materials (Yb:YAG and sapphire crystals) using the surface-activated direct bonding method based on etching the surfaces with an Ar ion beam and then bringing them into optical contact. Using a sapphire anti-ASE cap allows the thermal lens optical power and the M 2 factor to be reduced significantly compared with the same AE with a YAG anti-ASE cap, and M 2 compared to standard Yb:YAG disks without an anti-ASE cap. Lasing with 320 W average power and ∼ 50 % slope efficiency was obtained.

Correction for ‘Inkjet assisted fabrication of planar biocompatible memristors’ by Georgii A. Illarionov et al., RSC Adv., 2019, 9, 35998–36004.

We study, both experimentally and theoretically, the scattering of electromagnetic waves by a subwavelength hole fabricated in a thin metallic film. We employ the scanning near-field optical microscopy in order to reconstruct experimentally the full three-dimensional structure of the electromagnetic fields in the vicinity of the hole. We observe an interference of all excited waves with an incident laser beam which allows us to gain the information about the wave phases. Along with the well-known surface plasmon polaritons propagating primarily in the direction of the incident beam polarization, we observe the free-space radiation diffracted by the hole. We compare the experimental results with the fields of pure electric and pure magnetic dipoles as well as with direct numerical simulations. We confirm that a single hole in a thin metallic film excited at the normal incidence manifests itself as an effective magnetic dipole in the visible spectral range.

Here we present a method of particle pick-and-place manipulation, which is based on electrostatic interaction between objects charged under the beam of a scanning electron microscope. This method allows well-controlled pickup, transport and placement of micro- and nanoparticles as well as visualization of the process and the result of manipulation in real time on electron images. Manipulation of Al"2O"3, WO"3 and tungsten particles under the influence of the electric field proposed by a charged metalized tip was experimentally demonstrated. We also created a theoretical model, which is based on the assumption that the dielectrophoretic force created by the charged metallic tip pulls a particle whereas the van der Waals force retains it on a substrate.

Arrays of (Ga, Mn)As nanowire crystals are synthesized by molecular-beam epitaxy. Electronbeam lithography made possible the fabrication of electric contacts to individual nanowires. The influence of the annealing temperature on the properties of the contacts is studied. The optical annealing temperature is determined to be 160°C. It is found that an increase in the annealing temperature yields structure degradation. From studies of the current-voltage characteristics of the individual nanowire structures, a number of their electrical parameters, such as the resistivity and the mobility of charge carriers are determined.

Interest in heteroepitaxy of III-V compounds on Si has been growing rapidly in recent years due to the potential of the optoelectronic components integration on silicon. However, most of the semiconductor compounds conventional in optoelectronics cannot be easily integrated on Si substrates due to the formation of the lattice defects. In this paper, we consider the fabrication of the mask consisting of the ordered nanoscale holes with the use of microsphere photolithography for selective epitaxial growth – promising approach for nanostructures fabrication on mismatched substrates. We have carried out the calculation of electromagnetic wave absorption in the photoresist layer through 1.2 μm microspherical silica lenses. The theoretical optimization of the photoresist thickness parameter allowed to obtain a value at which the minimum holes diameter in the photoresist is achieved. These data are necessary for carrying out the process of lithography through microspherical lenses to create a patterned growth mask.

In this work, we use conductive atomic force microscopy (CAFM) to study the impact of substrate surface preparation and buffer layer composition on the electrical transport properties of GaN nanowires (NWs). I-V curves of single NWs from seven differently prepared samples were obtained. The tip of atomic force microscope (AFM) was used as a top conductive electrode to create stable electric contact to NW free upper grain, while the bottom contact was established between the highly doped Si substrate and a grounded sample holder of the AFM device. Single NW I-V curves were compared to those of NW arrays. The difference between them was discussed.

AlGaAs/GaAs solar cells (SC) was modeled. Conventional SC was compared with structure with the thinner emitter. SC with additional CNT transport layer was simulated and compared with SC without it. The simulation was carried out with different geometry of the contacts and light flux. CNT transport layer has allowed achieving an increase in SCs efficiency up to 1.7% compared with metal contact grid.