Том 52, № 16 (2018)
- Жылы: 2018
- Мақалалар: 38
- URL: https://journals.rcsi.science/1063-7826/issue/view/12756
Physics of Semiconductor Devices
Investigation of DC and RF Performance of Novel MOSHEMT on Silicon Substrate for Future Submillimetre Wave Applications
Аннотация
In this work, the DC and RF performance of a 20 nm gate length novel metal oxide semiconductor high electron mobility transistor (MOSHEMT) on Silicon substrate is studied using Sentaurus TCAD tool. The proposed MOSHEMT device features a novel T-gate structure, heavily doped In0.52Ga0.48As source/drain regions, delta doped planes on both sides of the In0.75Ga0.25As/InAs/In0.75Ga0.25As composite channel, a multi layer cap and a very thin layer of HfO2 as gate dielectric. The TCAD simulation results obtained at room temperature using hydrodynamic carrier transport model indicates that the 20 nm gate length proposed MOSHEMT device is capable of providing a peak drain current of 2450 mA/mm at VDS = 0.6 V and the peak transconductance obtained for the proposed device is 2900 mS/mm. The fT and fmax obtained for the Lg = 20 nm proposed MOSHEMT on Silicon substrate are 372 and 480 GHz respectively. At 300 K, the measured Hall mobility of the electrons in the quantum well channel is 9600 cm2/(V s). The on state resistance (RON) obtained for the Lg = 20 nm proposed device is 116 Ohm μm. These devices are undoubtedly, the most suitable candidates for future sub millimetre wave applications.
Simulation and Experimental Studies of Illumination Effects on the Current Transport of Nitridated GaAs Schottky Diode
Аннотация
In this paper, we studied the electrical characteristic of Schottky diodes based on gold contact on nitridated GaAs substrates. The used (100) GaAs substrate is n-type with concentration of Nd = 4.9 × 1015 cm–3. Nitridation process was performed using a N2 glow discharge source (GDS) creating N atomic species. A ultra-thin film with a thickness of 2.2 nm GaN is performed on GaAs surface. In order to study the electric characteristics under illumination, we use of a He–Ne laser of 1 mW power and 632.8 nm wavelength. The current–voltage (I–V) of the Au/GaN/GaAs structures was investigated at room temperature. The saturation current IS, the series resistance RS and the mean ideality factor n are, respectively, equal to 4.46 × 10–07 A, 172 Ohm, 1.4 in the dark and to 5.64 × 10–07 A, 148 Ohm, 1.21 under illumination. To analyze these results, a 1D-simulation code of forward and reverse current–voltage characteristics versus the critical parameters of a nitridated GaAs Schottky diode is implemented. The algorithm is based on the solution of the system composed by Poisson’s and continuities equations. In this calculation, we take into account the existence of the GaN layer and the localization of traps states in the perturbed interface. We have considered the W-shaped and U-shaped distribution of traps states in the band gap. The effects of the doping concentration of GaAs, the traps states density, light intensities and the work function of gold \({{\phi }_{m}}\) are investigated. By fitting the experimental curve, we can deduce the values of the traps states and the exact value of the work function of gold, and consequently we validate the developed model.
Diode Polarization and Resistive Switching in Metal/TlGaSe2 Semiconductor/Metal Devices
Аннотация
The influence of electric field and current flow on the current–voltage (I–V) characteristics of TlGaSe2 layered semiconductor was investigated by using a two-point probe measurement system. Threshold-type switching in I–V characteristics associated with current–controlled memory effect was observed in all investigated samples. Observed switching characteristic is close to the most experimentally realizable memristive systems. Experimental findings were analyzed by using a model of metal–insulator–semiconductor–insulator–metal (MISIM) structure having memristive behavior.
Semiconductor Structures, Low-Dimensional Systems, and Quantum Phenomena
Investigation of InGaAs/GaAs Quantum Well Lasers with Slightly Doped Tunnel Junction
Аннотация
We experimentally investigate and analyze the electrical and optical characteristics of InGaAs/GaAs conventional quantum well laser diode and the quantum well laser diode with slightly-doped tunnel junction. It was found that the laser with slightly-doped tunnel junction has a nonlinear S-shape current-voltage characteristic. The internal quantum efficiencies of the laser with slightly-doped tunnel junction and the conventional laser are 21 and 87.3%, respectively. This suggests that the slightly-doped tunnel junction increased the barrier width and free carrier absorption, thus could reduce the electron tunneling probability and increase the internal loss. Furthermore, compared with the conventional laser, it was found that we could achieve 15 nm broadband spectrum from the laser with slightly-doped tunnel junction, due to the lasing dynamics reflecting the current dynamics. The results show that the slightly-doped tunnel junction plays a crucial role in the laser diode performances, which may lead to the realization of more applications.
Critical Radius of Full Depletion in Semiconductor Nanowires Caused by Surface Charge Trapping
Аннотация
We have presented a simple analytical model for estimating critical radius of full depletion in semiconductor nanowires due to charge carrier transport from volume to the surface states and radial band bending associated with screening of trapped surface charges. The model describes the critical radius functional dependences on doping level, surface states parameters and appears as a very useful tool to understand transport properties of nanowires limited particularly by surface states effects.
Surfaces, Interfaces, and Thin Films
Near-Infrared InGaN Alloys Grown on High-In-Composition InGaN Buffer Layer
Аннотация
Near-infrared InGaN alloys were grown on a strain-relaxed high-In-composition InGaN buffer layer based on GaN/sapphire substrate by plasma assisted molecular beam epitaxy. The In compositions of the InGaN light emitting layer and buffer layer determined by X-ray diffraction analysis are 56.7 and 61.1%, respectively. Transmission electron microscopy result shows that no dislocations newly generated at the interface of the InGaN structure layer and the underlying InGaN buffer layer can be observed obviously. The cathodoluminescence spectra exhibit two strong emission peaks at the near-infrared wavelengths of 1090 and 1200 nm, which can be attributed to intrinsic transition and recombination processes of the fabricated InGaN alloys according to the calculation using the energy versus composition equation with a reasonable bowing parameter.
Microstructural Evolution of MOVPE Grown GaN by the Carrier Gas
Аннотация
We report the effect of total carrier gas flow of GaN during both GaN nucleation layer and high temperature GaN growth steps on structural, optical, electrical and morphological properties. The formation of dislocations in GaN layer and their effects were investigated in detail as a function of carrier gas flow. It has been found that the more carrier gas requires longer recovery time for transition from 3D (3 dimensional) to 2D growth and results in smaller edge-type dislocation density. The images obtained from the AFM measurements have shown terraces widths varying between 60–150 nm depending on the hydrogen flow rate.
Structural, Thermal and Luminescence Properties of AlN:Tm Thin Films Deposited on Silicon Substrate and Optical Fiber
Аннотация
Thin films of AlN:Tm are deposited on a Si(111) and Si(100) substrates and optical fiber by rf magnetron sputtering method. 200–400 nm thick films are deposited at various temperatures to observe the effect of temperature on their structure and morphology. Liquid nitrogen is used to deposit films at low temperature of –196°C. An electric heater is used to grow films at 250–700°C range. The deposited films are analyzed for their structure and thermal stability using X-ray diffraction and thermogravimetric analysis. Films deposited at liquid nitrogen temperature are amorphous and those deposited at high temperature are crystalline. Average grain size, strain and interatomic distance of the crystalline films are calculated. The grain size and inter-atomic distance increase from 36.54 to 45.12 nm and from 0.2368 to 0.25 nm respectively. Photoluminescence of the films excited by 783 nm crystal laser shows an intense infrared emission from Tm+3 at 802 nm as a result of 3H4 → 3H6 transition.
26th INTERNATIONAL SYMPOSIUM “NANOSTRUCTURES: PHYSICS AND TECHNOLOGY”. NANOSTRUCTURE CHARACTERIZATION
Stable and Unstable Spatial Modes in a Resonator with a Half-Disk Shape
Аннотация
This work was devoted to the study of stable and unstable optical modes in segment shaped resonators. The size of the studied resonators was much larger than the wavelength of the emitted light, that allowed to use the approaches of geometric optics. It was observed, that with an increase in the δ/R deviation parameter (where δ is the deviation from the center of the half-disk) only a small number of stable spatial modes remain. The possibility of the existence of “sealed” (non-radiating modes) and “open” modes (radiating modes) in resonators of this type was also shown.
Reflectometry of X-ray Whispering Gallery Waves Propagating along Liquid Meniscuses
Аннотация
X-ray reflectometry of whispering galleries (WGs), which propagate along meniscuses of deionized water or silica hydrosols (Ludox® SM) enriched by Cs+ ions, was analyzed for the first time. The measurements were performed using the diffractometer with a moving tube-detector system. The X-ray beam rotation angle reached a maximum value of 4° on a silica hydrosol sample at CuKα radiation, while for H2O it is only 1°. The intensities of WG modes propagating near the surface of a concave meniscus were found from the rigorous solution of the respective Helmholtz equation and applying the Monte Carlo technique for the random surface. For analysis of intensities of the X-ray scattering we used a hybrid model of the liquid surface with the upper transition layer having sinusoidal ripples in which the concentration of levitating Cs+ ions has a maximum near the surface, derived from the experiment, while the concentration maximum for SiO2 particles with sizes of ~6–15 nm is positioned at the depth of ~15 nm from the hydrosol’s surface. Our numerical results for reflectances are in a good agreement with the experimental data.
Polarization Properties of Photoluminescence of Anisotropic Polymer Films Containing Aligned Au Nanorods and Semiconductor Nanoparticles of Various Shape
Аннотация
Anisotropic polymer films containing aligned Au nanorods and semiconductor nanoparticles of various shape were fabricated. The photoluminescence of semiconductor nanoparticles in these films is partially polarized. The value of the photoluminescence polarization degree of quantum dots embedded in an anisotropic PVA-film after 4.5-fold stretching P = 0.27 has been obtained.
Сomposition Depth Profiling of the GaAs Native Oxide Irradiated by an Ar+ Ion Beam
Аннотация
The elemental and chemical compositions throughout the thickness of the GaAs native oxide layer slightly irradiated by Ar+ ions have been studied by synchrotron-based photoelectron spectroscopy at different photon energies enabling variation of probing depth. The presence of only two phases was observed: of the gallium oxide Ga2O3 and elementary arsenic Aso generated due to complete decay of arsenic oxides under the ion irradiation. Depth composition profiles were determined nondestructively. Despite inhomogeneous depth distribution, these profiles demonstrated domination (90 at %) of the dielectric Ga2O3 phase virtually throughout all the oxide thickness (~2 nm).
In situ Bandgap Determination of the GaAsN Nanolayer Prepared by Low-Energy \({\text{N}}_{2}^{ + }\)Ion Implantation
Аннотация
An approach to solving the problem of the in situ bandgap determination in the extremely thin and chemically active nitride nanolayers fabricated in high vacuum on the n-GaAs surface has been suggested. The approach is based on measuring the interband transitions involving the quantum well states by the method of electron energy loss spectroscopy. The bandgap of the nitride layer formed on the GaAs surface by low-energy \({\text{N}}_{2}^{ + }\) ion implantation was determined to be 0.2 eV less than that of GaAs, which evidenced for creation of the GaAsN dilute alloy on the GaAs surface.
Atomic Force Microscopy Study of Monodisperse Carbon Nanoparticles
Аннотация
Monodisperse carbon nanodots and nanodiamond particles were studied by AFM method. Particle size distributions were calculated using AFM and DLS data. The results obtained correspond to TEM measurements. It was demonstrated that AFM allows detecting nanoparticles with sizes less than 2 nm. The average size of the particles for both samples was found to be ~4 nm. It was found that PSD for CND and DND was symmetric and asymmetric, correspondingly. Such difference can be understood in terms of different crystal structure perfection and the specific aspects of nanosized carbon preparation technology.
Polarized Retroreflection from Nanoporous III–V Semiconductors
Аннотация
“Retroreflected light with strong linear polarization coinciding with that of the incident beams is detected from strongly absorbing nanoporous III–V semiconductors. Because of high polarization of retroreflected waves we assume that coherent backscattering is the underlying physical mechanism of this phenomenon”.
XAFS Investigation of Nanoparticle Formation in 64Zn+ Ion Implanted and Thermo Oxidized Si
Аннотация
The single crystal CZ n-Si(100) substrates with electron concentration no = 5 × 1016 cm−3 were implanted by 64Zn+ ions with dose of 5 × 1016 cm−2 and energy of 50 keV. During implantation the ion beam current density was less than 0.5 μA/cm2 to avoid the substrate magnetically heating. After implantation, the plates were subjected to isochronous for one hour heat treatment in oxygen atmosphere at temperatures from 400 up to 1000oC with a step of 100oC. Zn K-edge EXAFS spectra were measured in fluorescent mode. Si(111) channel-cut monochromator was used for energy scanning; energy resolution ΔE/E = 2 × 10–4. According to Zn K-edge EXAFS data, all Zn implanted in Si at 900oC is fully oxidized: an absolute maximum of EXAFS Fourier transform at R ~ 1.6 Å corresponds to Zn–O distance. Based on XANES data, we suggest an interaction between implanted Zn atoms and Si support.
Growth of Textured Au–Fe/Fe Hybrid Nanocrystals on Oxidized Silicon Surface
Аннотация
We present in this report the route to produce highly-textured Au3Fe(111)/Fe(110) hybrid nanocrystals on an amorphous surface of SiO2/Si by molecular beam epitaxy. By controlling the quantity of Au atoms deposited onto the SiO2/Si it is possible to tune the average lateral size of resultant Au–Fe hybrid nanocrystals from 10–20 nm up to 100–150 nm at the same Fe nominal thickness deposited. This process is sensitive to the initial density and size of Au islands. Examination of Au–Fe hybrid nanocrystals obtained was carried out using X-ray diffraction, transmission and scanning electron microscopy, reflection high energy electron diffraction, and Kerr effect methods.
Influence of the Pore Structure on the Electron Barrier Height of Metal-Ceramic Nanomaterials Based on Gold-Anodic Aluminum Oxide
Аннотация
The influence of the of the pore structure on the electron barrier height of Au–Al2O3 structures is experimentally studied. The porous structures of anodic aluminum oxide of two types with through pores and pores in the form of a well are investigated. It is shown that, depending on the shape of the pore profile, the deposited thin gold film creates a different height of the electron barrier at the metal-insulator interface. The method of linear optical spectroscopy showed that the height of the barrier for structures with through pores is higher by 2.0 eV.
26th INTERNATIONAL SYMPOSIUM “NANOSTRUCTURES: PHYSICS AND TECHNOLOGY”. NANOSTRUCTURE TECHNOLOGY
Atomic Force Microscopy Local Oxidation of GeO Thin Films
Аннотация
Metastable germanium monoxide (GeO) thin-insulating films have been investigated as a new promising material for atomic force microscope (AFM) oxidation lithography. The kinetics of GeO layer oxidation performed in the tapping mode of AFM was found to have a logarithmic relationship to oxide height versus pulse duration. Effect of humidity on oxidation of germanium monoxide thin films was studied at relative humidity 40, 60, 80%. When local anodic oxidation of GeO layer was carried out by AFM operating in the contact mode in high voltage (≥9 V) regime and at high relative humidity (RH = 80%), the size and shape of fabricated oxide was changed drastically.
Growth Modes of GaN Plasma-Assisted MBE Nanowires
Аннотация
Within this work we study the plasma-assisted molecular beam epitaxy of GaN on Si(111) substrate at different substrate temperatures and III/V flux ratios. We present the model, which gives the analytical expressions for the boundaries between the three growth modes: compact layer, nanowires, and absence of growth. We extract the activation energy for nucleation of GaN nanowires on the Si(111) from the model fitting to experimental data.
Microlens-Enhanced Substrate Patterning and MBE Growth of GaP Nanowires
Аннотация
In this paper we demonstrate the results on selective area growth of GaP nanowires via self-catalyzed growth method using molecular beam epitaxy (MBE) technique on patterned Si(111) substrates. The pattern fabrication method on a base of the photolithography process over an array of microspherical lenses has been studied theoretically and then optimized in order to obtain the nanostructures with controlled morphology. It was found that the positive resist thickness corresponding to the best achievable resolution in the subwavelength region is 250 nm in case of 1.5 μm silica spheres and excitation with 365 nm LED. The silica growth mask for selective epitaxy was fabricated. The ordered array of GaP nanowires was synthesized with MBE. Large scale ordering and selectivity of the growth technique is demonstrated.
Self-Catalyzed MBE-Grown GaP Nanowires on Si(111): V/III Ratio Effects on the Morphology and Crystal Phase Switching
Аннотация
Self-catalyzed GaP nanowire and GaP/GaPAs nanowire heterostructures have been grown on Si(111) by solid-source molecular beam epitaxy. Formation of wurtzite polytype segments with thicknesses varying from the several tens up to the 500 nm depending on the growth condition has been observed. Effect of the V/III flux ratio on the growth mechanism, nanowire structure and morphology was studied by means of scanning electron microscopy and high resolution transmission electron microscopy.
InGaN/GaN QDs Nanorods: Processing and Properties
Аннотация
InGaN/GaN nanorod structure is presented for the fabrication of light-emitting diodes by means of plasma-chemical etching. Processes of the etching of nanorods and the defect passivation in a planar InGaN/GaN quantum dot heterostructure are studied. The obtained results allow creating the light-emitting diode nanostructure with a greater efficiency compared to the classical planar technology.
Formation and Properties of New Types of Metal–Dielectric Nanostructures for Creating Optical Metamaterials
Аннотация
“Herein, we consider the technologies of obtaining composite structures that can exhibit the properties of metamaterials, namely layered metal–dielectric (metal–polymer) structures and fish-net metal-polymeric structures. The dielectric and resonance properties of the synthesized structures are studied both theoretically and experimentally, and the excitation features of new types of quasi-non-diffraction plasmon-polaritons generated in them are established. Original methods and tools for characterizing the optical properties of the created composite structures (in particular, a differential polarization interferometer, a method and a device for detecting a negative refractive index) are proposed. Based on the developed and created metamaterials, a number of new devices are proposed and implemented, in particular, new configurations of flat lenses (so-called superlenses) of the near and far fields in the spectral range from ultraviolet to infrared radiation”.
New Advanced Hybrid Organic–Inorganic Complex
Аннотация
New hybrid organic–inorganic complexes of perylene with nanodiamonds were developed and fabricated. The fact of complex formation was confirmed by the analysis of the infra-red (IR) absorption spectra and their spectral-luminescent properties. It was shown as a result of nanodiamond (ND) template synthesis that in new complexes based on NDs occur appearance of strong structured excitation bands in the ultra violet (UV) region of spectrum, within 230–300 nm. The formation of new UV excitation centers in complexes leads to a significant enhancement of luminescence in the green region of the spectrum.
MBE AlGaN/GaN HEMT Heterostructures with Optimized AlN Buffer on Al2O3
Аннотация
The effect of molecular-beam epitaxy (MBE) growth conditions on properties of AlN epitaxial layers was investigated resulting in determination of optimal substrate temperature and ammonia flow. Optimal substrate temperature for growth of GaN and AlGaN layers was determined analyzing thermal decomposition rate of GaN. Based on the information, high electron mobility transistor heterostructures were grown on sapphire substrates using both ammonia and combined plasma-assisted/ammonia MBE modes. The highest achieved 2DEG mobility was 1992 cm2/(V s) (at 2DEG density of 1.17 × 1013 cm–2) which is the current state-of-the-art level.
Structural Transformation of “Silica+Zn” Nanocomposite after Annealing in Oxidizing Atmosphere
Аннотация
It has been found that “hot” high-fluence Zn+ implantation leads to the formation of the extended layer with zinc-based nanoclusters of size up to 10 nm in SiO2 film. The precipitate’s crystalline nature is confirmed by HRTEM studies. Post-implantation annealing at 700°C for 60 min leads to Zn atoms redistribution in implanted region, formation of the larger crystallites (up to 25 nm) and the small Zn nanoparticles surrounded by the oxide shells (core (Zn)/shell(ZnO) structure) as well as the voids formation at the interface “Zn nanocluster/SiO2 matrix”. The number of the core (Zn)/shell (ZnO) structures and the voids increases after annealing at 700°C for 120 min.
Processing of GaN/Si(111) Epitaxial Structures for MEMS Applications
Аннотация
Two different approaches for the etching of the gallium nitride epitaxial layers grown on Si(111) substrates by plasma-assisted molecular beam epitaxy have been elaborated. It is demonstrated that anisotropic etch profiles can be achieved by both photoenhanced wet chemical etching and reactive plasma-chemical etching methods. Moreover, it is shown, that the photoenhanced wet chemical etching allows to remove GaN layer without damaging silicon substrate.
Estimation of Evaporation Rate from Gold-Silicon Alloy Based on the Nucleation Time and Nanowire Length Distributions
Аннотация
Nanowires are one of the most promising building blocks for various nanoelectronic devices. Nanowires are usually grown via the so-called vapor-liquid-solid mechanism on the surfaces activated by the droplets of a catalyst (e.g., Au). Here we theoretically studied the impact of the evaporation from the droplet on the nucleation statistics. Within the semi-analyticalapproach, we obtain the relation between the nucleation time distributions and the evaporation rate of atoms from the droplet. We analyze the Si NW length-time dependences to estimate theeffective lifetime of a silicon atom in a gold-silicon alloy at 550°C is about 5 s.
Two Methods of Calculation Ternary Nanowire Composition
Аннотация
The growth of ternary nanowires via the vapor-liquid-solid mechanism is one of the possible ways of band gap engineering. However, the dependence of ternary nanowire composition on growth parameters is still unclear. We compare two theoretical approaches to ternary nanowire composition determined either by the formation of the critical island or by the step-flow growth of the monolayer. For typical parameters of gold-catalyzed growth, these two models give similar results. In the case of self-catalyzed growth, the step-determined model predicts higher In content in the NW than the island-determined.
Heteroepitaxy of GaP Nucleation Layers on Si by Molecular Beam Epitaxy
Аннотация
The growth of single crystalline GaP nucleation and buffer layers on Si substrates by molecular-beam epitaxy is demonstrated. The use of two different regimes of migration-enhanced epitaxy was studied. It was found that p–n junctions can be created due to the interdiffusion during the growth of GaP layer on p-type Si substrate.
Nucleation and Growth Modeling of Protein Crystals in Capillaries
Аннотация
Within this work we model the spatial dependences of protein concentration, nucleation probability and the radius of lysozyme crystal in the experiments on capillary counter-diffusion crystallization. Within the model approach, we evaluate the conditions for the formation of lysozyme crystals with the target separation of 100 µm between centers of protein crystals. The predicted and observed number density, sizes and positions of protein crystals in capillary are in excellent agreement.
Monte Carlo Simulation of Ga Droplet Movement during the GaAs Langmuir Evaporation
Аннотация
A kinetic lattice Monte Carlo model is used to study the Ga droplets self-propelled motion along GaAs(111)A and (111)B surfaces during the initial stage of high-temperature annealing. An estimation of the droplet velocity, running along (111)A and (111)B surfaces, in a wide temperature range, is carried out. The mechanism of small Ga drops movement during high-temperature annealing is suggested. Different directions of droplets motion and the morphology of drop-crystal interface on (111)A and (111)B substrates are determined by a difference in the etching rate of (111)A and (111)B facets by liquid gallium. It is shown that metal droplets can cause step bunching.
Luminescent Silicon Nanocrystals Prepared by Laser-Assisted Synthesis in Liquid for Imaging and Photovoltaic Applications
Аннотация
Silicon nanocrystals (SiNCs) with photoluminescence in the visible spectral range were synthesized by laser irradiation of silicon wafers in solutions. Laser irradiation leads to the formation of well-dispersed Si–NCs with an average diameter of about 5 nm, which upon excitation with 300−450 nm light exhibited room temperature luminescence tunable in the range from 410 to 650 nm. The results showed that photoluminescence (PL) is affected by both sizes and surface states of the Si–NCs. The results obtained allow to conclude that the synthesized nanoparticles (NPs) can be suitable materials for applications in fluorescence imaging along with photovoltaics.
26th INTERNATIONAL SYMPOSIUM “NANOSTRUCTURES: PHYSICS AND TECHNOLOGY”. QUANTUM WELLS AND QUANTUM DOTS
Manganese Doped Zinc Sulfide Quantum Dots as Efficient Photocatalyst for Dye Decolorization
Аннотация
A simple aqueous based synthesis technique at room temperature was performed for preparation of pure and manganese (Mn2+) doped ZnS quantum dots in the presence of glutathione as the capping agent. Under UV-excitation quantum dots show photoluminescence bands at 2.13 and 3.0 eV corresponded to Mn2+ and intrinsic ZnS emission respectively. ZnS quantum dots were used as the photocatalyst to remove organic dyes in aqueous solution, with methylene blue as a model dye. The influence of the Mn2+ concentration on the dye degradation efficiency was studied. The highest photocatalytic degradation rate of methylene blue was obtained for ZnS quantum dots in glutathione shell doped with 0.125 at % of Mn2+.
Structural and Optical Properties of Wurtzite AlGaAs Nanowires Grown by MBE on Si(111) Substrate
Аннотация
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.
Plasmonic Enhancement of the Photoluminescence in Hybrid Structures with SiGe Quantum Dots and Ag Nanoislands
Аннотация
Plasmonic enhancement of the photoluminescence in hybrid structures with SiGe quantum dots and Ag nanoislands was found. Ag nanoislands grown on the top of the multilayer structures with SiGe quantum dots (QDs) support a surface plasmon resonance that can be tuned to the QD emission wavelength by changing of Ag nanoparticle parameters. Photoluminescence measurements of the hybrid metal-semiconductor nanostructures revealed a fourfold increase of the integral intensity of SiGe QD emission in the spectral range from 0.8 to 1 eV.