Binary Compound Semiconductors Research Articles

Transition Metal Oxide Nanomaterials: New Weapons to Boost Anti-Tumor Immunity Cycle.

Semiconductor nanomaterials have emerged as a significant factor in the advancement of tumor immunotherapy. This review discusses the potential of transition metal oxide (TMO) nanomaterials in the realm of anti-tumor immune modulation. These binary inorganic semiconductor compounds possess high electron mobility, extended ductility, and strong stability. Apart from being primary thermistor materials, they also serve as potent agents in enhancing the anti-tumor immunity cycle. The diverse metal oxidation states of TMOs result in a range of electronic properties, from metallicity to wide-bandgap insulating behavior. Notably, titanium oxide, manganese oxide, iron oxide, zinc oxide, and copper oxide have garnered interest due to their presence in tumor tissues and potential therapeutic implications. These nanoparticles (NPs) kickstart the tumor immunity cycle by inducing immunogenic cell death (ICD), prompting the release of ICD and tumor-associated antigens (TAAs) and working in conjunction with various therapies to trigger dendritic cell (DC) maturation, T cell response, and infiltration. Furthermore, they can alter the tumor microenvironment (TME) by reprogramming immunosuppressive tumor-associated macrophages into an inflammatory state, thereby impeding tumor growth. This review aims to bring attention to the research community regarding the diversity and significance of TMOs in the tumor immunity cycle, while also underscoring the potential and challenges associated with using TMOs in tumor immunotherapy.

Electronic structure, optical and elastic properties of Si doped Strontium Selenide: A theoretical investigation

The structural, electronic, optical, and elastic properties of Silicon doped Strontium Selenide binary and ternary semiconductor alloys with the general form of Sr(1-x)SixSe, 0 ≤ x ≤ 1 in B1 and B3 phases have been figured adopting augmented plane wave plus local orbital methods within density functional theory, Structural properties summarize the crystal structure, relevant atomic positions, lattice constant, bulk modulus minimum energy E0 and minimum volume V0. Elastic constants conform to the structure stability of the B1 and B3 phases. Band gap is found to shift from indirect to direct and in some materials with initial direct band gap, the gap width increased which increased the range of applicability of these binary and ternary semiconductor compounds. Whereas optical properties which include the study of zero frequency limit of static dielectric constant ε0(ω) with its real and imaginary parts, static refractive index n(0), optical reflectivity (R), optical absorption coefficient (α), and loss function (L) studied comprehensively to get real electrical and optical properties of these materials and give semiconductor market best alternative candidate which shows its effectiveness in the visible, ultraviolet and infrared region of the electromagnetic spectrum. The obtained results were compared together and with the available experimental along with theoretical work on these binary and ternary Silicon doped Alkaline earth chalcogenides.

Growth of single crystal Sb2S3 semiconductor pillars by sol-gel method

The binary compound semiconductor Sb2S3 was fabricated on solid substrate by spin coating based on a sol-gel method. In this study, it was observed that crystallinity appeared differently depending on the type of substrate material used to fabricate the Sb2S3 structure, and this mechanism was investigated. As the substrate, bare FTO glass and FTO glass coated with Mo, Ni, and Au were used. In the case of Sb2S3 grown on bare FTO glass and FTO glass coated with Mo, crystals are formed in-plane, whereas in the case of Sb2S3 grown on FTO glass substrate coated with FCC-structured metals such as Au and Ni, crystals are formed out-of-plane. It was observed that the single crystal growth of rectangular pillar-shaped Sb2S3 was closely related to the formation of regularly ordered compounds at the interface between the Sb2S3 pillar and the FCC metal substrate.

Porous Semiconductor Compounds with Engineered Morphology as a Platform for Various Applications

Porous semiconductor compounds represent a class of materials which is under an intense research focus over the last years. Herein, morphologies and topologies produced by anodization in binary semiconductor compounds having various bandgaps and crystallographic orientations are demonstrated with a focus on technological procedures applied for generating arrays of pores with a controlled design. The mechanism of pores growth under the photoresist masks is discussed and the connection between the design of the mask and the architecture of the produced porous structure is disclosed. The evolution of physical characteristics of the materials such as luminescence, optical, photonic, vibrational, hydrophilic, and hydrophobic properties as a result of anodization is investigated. Investigations are performed by means of scanning electron microscopy, photoluminescence and cathodoluminescence spectroscopy, and contact angle measurements. Some possible practical applications of the proposed technological approaches and the produced porous structures are briefly discussed.

Effect of Plant Nanocellulose Electrolyte, Zinc Oxide Nanoparticles, and Nano-Chlorophyll Sensitiser on the Dye-Sensitised Solar Cell Performance

Owing to ecological concerns and the rapid increase in fossil fuel consumption, sustainable and efficient generation technologies are being developed. The present work aimed at manufacturing DSSC that is based on natural elements for converting the sun energy into electrical energy. ZnO nano materials are used in solar cells as binary compound semiconductor according to their stability, better conductivity, excellent mobility, the best affinity of electrons, and lower cost compared to other semiconductors. Recently, nanocellulose has shown potential as an advanced nanomaterial used in electrochemical conversion devices since it is considered the best abundant Earth biopolymer and is inexpensive and versatile. The constructed DSSC composed of plant nanocellulose (PNC) extracted from banana peel and nano-chlorophyll dye extracted from aloe vera were evaluated as the electrolyte and sensitiser, respectively. With increasing PNC content from 0 to 32 wt.%, both PV parameters and lifetime increase, and voltage decay decreases. The nano particles size modification for three materials carried by ultrasonic waves. Increasing the ultrasonic wave exposure time reduced the size of the Chl particles. The addition of PNC from banana peel to DSSC electrolyte is shown effective. The effect of varying the PNC/nano-chlorophyll content (0–32 wt.%) on the photovoltaic parameters of the DSSC was investigated. The addition of PNC significantly increased the fill factor and sunlight conversion efficiency. The DSSCs showed acceptable performance under relatively low irradiation conditions and different light intensities, indicating that they are suitable for outdoor applications.

Investigation of radiation response for III-V binary compound semiconductors due to protons using Geant4

The III-V binary compound semiconductor is considered to be an appealing candidate for future complementary metal oxide semiconductor applications and the most promising silicon substitute in terms of high electron mobility. In this study, the authors used the Monte Carlo simulation software Geant4 and the data analysis tool Python to comprehensively examine the interaction between protons with a wide range of energy and III-V binary compound semiconductors. This work focus on the radiation responses of 11 kinds of III-V materials—AlAs, AlP, AlSb, GaAs, GaN, GaP, GaSb, InAs, InN, InP, and InSb—with silicon as a reference. Energy straggling, secondary ion generation, and energy distribution in the sensitive layer were represented in each simulation of the incident protons. Information about the distributions of the linear energy transfer of the secondary ions and energy deposition was acquired through data analysis. Finally, the impact of the material species on the single-event upset responses triggered by the direct ionization and the nuclear reaction mechanisms at different critical charges were investigated.

Comparisons of visible-light driven photocatalytic CO2 conversion performances over mesoporous CdSxSe1–x with different molecular compositions

This study presents a synthesis method for nanowire arrayed mesoporous CdSxSe1-x compounds with different S/Se molar ratios. Both ternary and binary compound semiconductors are synthesized by hard-templating using SBA-15 as a silica template. The synthesized mesoporous materials have high specific surface areas of approximately 65–100 m2 g−1 and remarkable light absorption properties in the UV to visible light region (1.7–2.4 eV), and thus they are appropriate for the photo-conversion of CO2 into CO and CH4. The results show that the compositions of CdSxSe1-x excellently agree with the compositions of the reactants. Moreover, the band gaps of the mesoporous CdSxSe1-x samples could be directly tuned by varying the composition of the reactants. It is concluded that mesoporous CdSe achieves the highest CH4 yield rate, i.e., 0.382 μmol gcat–1 h–1, and CdS0.5Se0.5 achieves the highest CO yield rate (among all the samples synthesized), i.e., 5.633 μmol gcat–1 h–1. Also, it is found that the CO2 photoconversion performance on mesoporous II-VI photocatalyst are highly affected by CO2 adsorption capacities and photo-generated charge separation.

Density Functional Theory Approach to the Study of the Structural Stability of Nitrides of Iron and Nickel

Nitrides of transition metals such as iron and nickel are known to possess excellent properties relevant for technological applications. Among these, FeNhas been synthesized in zinc blende face centered cubic (F4 M) crystal structure while NiN has not been synthesized yet. Literature search revealed that hexagonal close packed and primitive tetragonal structures of these compounds have not been investigated to ascertain their preference.Therefore, the structural stability of Zinc blende face centered cubic, hexagonal closed packed and primitive tetragonal crystal structures of the compounds were investigated in this study. Generalized gradient approximation of Perdew-Burke-Ernzerhof revised for solids (GGA-PBEsol) as implemented in Quantum espresso package was used based on density functional theory for the computation. The results revealed that FeN and NiNcompounds prefer Zinc blende face centered cubic crystal structure as their equilibrium lattice parameters occurred at the least equilibrium minimum energies in this structure. The lattice parameters of FeN and NiN compounds in thezinc blende FCC crystal structure were computed to be 4.232 Å and 4.324 Å respectively in agreement with experiment and previous computations. The preference of zinc blende FCC crystal structure by these compounds imply they may possess highly directional covalent bonds that prefer a tetrahedral arrangement of atoms, thus forming good binary semiconductor compounds. Therefore, these compounds have high possibility of been synthesized in zinc blende FCC crystal structure.

半导体纳米线红外探测研究进展（特邀）

In recent years, infrared photodetectors have attracted increasing interest due to their promising applications in both military and civil areas. To further realize room-temperature, wide-spectrum, high-sensitivity, fast-response and low-power consumption infrared photodetectors, low-dimension semiconductors are considered as potential channel materials and have been studied widely. Among them, nanowires have special electrical and photoelectrical characteristics, showing enormous advantages in the applications of infrared photodetectors such as small size, low power consumption, high light absorption efficiency, abundant surface states, outstanding ability to separate and collect photoelectrons, good compatibility with Si complementary metal-oxide-semiconductor (CMOS) technology and so on. At present, nanowires infrared photodetectors are going through continuous progress and breakthrough. In this review, recent advances in semiconductor nanowires infrared photodetectors were outlined in details. At the beginning, the basic characteristics, material choice and preparation methods of nanowires were introduced. Subsequently, many nanowires including binary and ternary compound semiconductors for the use of infrared detection were presented and their current detectable levels were illustrated precisely. Many methods of further improving their detecting performances were also classified and summarized, including constructing heterostructures, applying external field and integrating with other functional devices. On the basis of the above-mentioned advances, a comparison of advantages and disadvantages among different nanowires infrared detectors was given. In the end, the future development trend was indicated based on the challenges in this area and preliminary suggestions for the technical development route were presented.

Observation of mixed types of energy gaps in some II–VI semiconductors nanostructured films: towards enhanced solar cell performance

All solid-state quantum dots embedded multi-junction solar cell with the device structure of (Glass/ITO/ZnTe/ZnS/CdS/Au) is achieved to boost the photo-conversion efficiency by incorporating inner layer of ZnS and by effectively utilizing the entire solar spectrum. Electron beam evaporation was used to deposit the three semiconductor materials ZnTe, ZnS and CdS thin films. The optical properties and energy bandgap of each of the three materials were determined using ellipsometric measurements. The device performance was investigated using current voltage (J–V) techniques at room temperature and under AM1.5 illumination conditions. In this study, we showed that the optical energy gaps of some nanoscale binary semiconductor compounds from II–VI family exhibit both direct and indirect types of optical energy bandgap and there is a giant increase in their direct values.

Quantifying the Transverse-Electric-Dominant 260 nm Emission from Molecular Beam Epitaxy-Grown GaN-Quantum-Disks Embedded in AlN Nanowires: A Comprehensive Optical and Morphological Characterization.

There has been a relentless pursuit of transverse electric (TE)-dominant deep ultraviolet (UV) optoelectronic devices for efficient surface emitters to replace the environmentally unfriendly mercury lamps. To date, the use of the ternary AlGaN alloy inevitably has led to transverse magnetic (TM)-dominant emission, an approach that is facing a roadblock. Here, we take an entirely different approach of utilizing a binary GaN compound semiconductor in conjunction with ultrathin quantum disks (QDisks) embedded in AlN nanowires (NWs). The growth of GaN QDisks is realized on a scalable and low-cost Si substrate using plasma-assisted molecular beam epitaxy as a highly controllable monolayer growth platform. We estimated an internal quantum efficiency of ∼81% in a wavelength regime of ∼260 nm for these nanostructures. Additionally, strain mapping obtained by high-angle annular dark-field scanning transmission electron microscopy is studied in conjunction with the TE and TM modes of the carrier recombination. Moreover, for the first time, we quantify the TE and TM modes of the PL emitted by GaN QDisks for deep-UV emitters. We observed nearly pure TE-polarized photoluminescence emission at a polarization angle of ∼5°. This work proposes highly quantum-confined ultrathin GaN QDisks as a promising candidate for deep-UV vertical emitters.

Triplet grain growth in a-texture polycrystalline ZnO thin films

A growth of grain triplets is identified in vapor deposited, a-texture polycrystalline zinc oxide thin films, using a combination of transmission electron microscopy-based automated crystal orientation mapping and high-resolution imaging. Each triplet consists of three wurtzite phase grains, coordinated to near tetrahedral relative growth angles by the close-packed planes of a few nanometer diameter core of metastable zinc blende phase ZnO located at their triple junction. The triplets are aligned such that two of the grains have their fast growing [21¯1¯0] axes (near-) parallel to the substrate normal, and so coarsen under the principle of competitive grain growth. In contrast, growth of the third grain with a (101¯3) texture is impeded, such that it forms a small wedge between the ends of its two larger neighbors. Remarkably, all three boundaries between the grains adhere to a [21¯1¯0]/(011¯3) coherent twin orientation relationship, which corresponds to a grain geometry that is incommensurate with a perfect crystallographic nature. This coherency is primarily achieved via the small grain having an orientation that rotates internally by 10±2° across its volume, when going between the two interfaces formed with the neighboring large grains. The energy associated with this structural distortion is compensated by the formation of the coherent twin boundaries, such that the triplets are a stable or semi-stable growth form that are abundant in the film. The small (101¯3) texture grains may renucleate persistently, taking either of two possible orientations from the underlying tetrahedral coordination. By developing a phenomenological model for the triplet geometry and form, we associate these two orientations to small hexagonal caps and angled wedges seen in the surface morphology of the film. These findings potentially carry relevance for a wide range of vapor deposited compact films and free-standing nanostructures of wurtzite phase octet binary semiconductor compounds. We therefore believe that these insights can stimulate new research, for instance to obtain a more fundamental understanding of the growth mechanisms at the atomistic level.

Analysis of Phonon Modes and Electron–Phonon Interaction in Quantum-Cascade Laser Heterostructures

The phonon modes of quantum-cascade heterostructures based on binary and ternary semiconductor compounds are simulated. The dependences of the frequencies of the structure interface phonon modes on the wave vector in the layer plane and on the phase shift in the superlattice period are calculated. It is found that the range of variation in the quantum energy of phonon modes of the GaAs/Al0.25Ga0.75As structure does not exceed 2 meV. The calculated resulting interband scattering rate in the structure, taking into account the interface and confined modes, barely differs from that calculated in the bulk phonon approximation.

Ternary alloyed HgCdTe nanocrystals for short-wave and mid-wave infrared region optoelectronic applications

Semiconductor quantum dots (QDs) are emerging as the forefront alternative for the conventional imaging technology, particularly in infrared region from near infrared (0.75–1.4 μm) to long-wave infrared (8–14 μm) region. A handful of materials are explored for mid infrared imaging QDs and they are all invariably binary semiconductor compounds. Ternary alloyed quantum dots in many previous cases have shown properties that are unique and better than parent binary compounds. In this work, we have synthesized ternary alloyed HgCdTe quantum dots and studied their photophysical properties. Previously studied ternary alloyed HgCdTe CQDs absorb and emit in regions limited upto near-infrared region. We have tuned the excitonic absorption of HgCdTe QDs in the range of 2.2–5 μm, where addition of cadmium clearly showed blueshift in excitonic peak as compared to that of HgTe QDs. Structural properties are studied by TEM, XRD & XPS techniques. Electrical behaviour is studied by measuring I-V, I-V-T curves. Photodetectors are fabricated in photoconductive geometry showing promising photo-response under visible (532 nm) and NIR (810 nm, 1550 nm) excitation. Responsivity of the devices is in the order of 1 mA W−1 at 1 V bias and show good linearity over irradiance range of 0.025 and 2.5 W cm−2. These results pave the way for development of next generation cost-effective short-wave and mid-wave infrared region optoelectronic devices based on narrow bandgap HgCdTe nanocrystals.

Atmospheric Neutron Radiation Response of III–V Binary Compound Semiconductors

This article is a first attempt to explore, by simulation, the radiation response of III-V binary compound semiconductors subjected to high-energy atmospheric neutrons. The study focuses on the radiation response of eight III-V materials: GaAs, AlAs, InP, InAs, GaSb, InSb, GaN, and GaP. For each semiconductor, the interaction rates of a bulk material target exposed to a neutron source mimicking the atmospheric neutron spectrum at sea level are evaluated both from a direct calculation using nuclear cross section libraries and by Geant4 simulations. The latter are also used to investigate in detail the reaction rates per type of reaction (elastic, inelastic, and nonelastic) and to classify all of the neutron-induced secondary products considering their atomic number and energy. Implications for single event effects are analyzed and discussed, notably in terms of electrical charge deposited in the material with respect to the critical charge for technologies ranging from 180 to 14 nm.

Effects of substrate temperature and SnO2 high resistive layer on Sb2Se3 thin film solar cells prepared by pulsed laser deposition

Sb2Se3, an emerging promising binary compound semiconductor, was prepared at different substrate temperatures by pulsed laser deposition for thin film solar cells for the first time. In this work, CdS and Sb2Se3 films were subsequently deposited by pulsed laser deposition to simplify the process. Film properties and device performance, closely related to the substrate temperature, were characterized by thermal gravimetric analysis, X-ray diffraction, UV–Vis–NIR spectrophotometer, scanning electron microscope, light and dark current density-voltage, external quantum efficiency and capacitance-voltage, respectively. Results indicate that Sb2Se3 solar cells film deposited at 500 °C is better, with a better efficiency of 3.58%. Furthermore, SnO2 high resistive layer was introduced into Sb2Se3 solar cell to improve the junction quality, leading to a champion device efficiency of 4.41%.

XXIV Международный симпозиум Нанофизика и наноэлектроника", Нижний Новгород, 10-13 марта 2020 г. Анализ фононных мод и электрон-фононного взаимодействия в квантово-каскадных лазерных гетероструктурах

The phonon modes of quantum cascade heterostructures based on binary and ternary semiconductor compounds are modeled. The dependences of the frequencies of the interface phonon modes of the structure on the wave vector in the plane of the layers and on the phase shift in the period of the superlattice are calculated. It was found that the range of variation of the quantum energy of the phonon modes of the GaAs/Al0.25Ga0.75As structure does not exceed 2 meV. The calculated resulting interband scattering rate in the structure, taking into account the interface and confined modes, practically does not differ from the calculations in the approximation of bulk phonons of the structure.

Annealing and surface treatment effect on the optical and electrical properties of n-type CdS binary compound semiconductors

The preparation of CdS thin films were actualised with electrodeposition technique using cathodic voltage of 1200 milli – Volts (mV). The optical and electrical properties of three different classes of CdS semiconductors namely as – deposited CdS layers (AD-CdS), CdS layers heat-treated in air without any chemical treatment (HT-CdS) and CdS layers treated with CdCl2 and annealed in air (CC-CdS) have been investigated in this work. Results from optical analysis showed that AD-CdS layers have the least absorption edge and highest energy bandgap. Annealing the CdS thin films without and with CdCl2 treatment brings the energy bandgap to same value of ~2.42 eV. The main distinction between the HT- and CC-CdS layers is that the absorption edge of CC-CdS films is sharper than the HT-CdS. Results from electrical analysis revealed that the magnitude of photo-electro-chemical (PEC) cell signals which give a clue about the doping concentration of the semiconductor material is greater in CC-CdS layers than in AD- and HT-CdS layers.Keywords: AD-CdS, HT-CdS, CC-CdS, Energy Bandgap, Absorption Edge, PEC Cell Signal.

Two-dimensional Bi2S3-based all-optical photonic devices with strong nonlinearity due to spatial self-phase modulation

Abstract Bismuth sulfide (Bi2S3) is a binary chalcogenide semiconductor compound that has received much attention in optoelectronic devices because of its stratified structure. In this work we showed that the two-dimensional (2D) Bi2S3 shows strong nonlinearity using spatial self-phase modulation and that the all-optical photonic devices, e.g. the all-optical switches and all-optical diodes, have been demonstrated experimentally by observing the nonlinear behavior of the diffraction rings. In addition, an all-optical diode is designed in this work using combined structure with 2D Bi2S3/SnS2 nanosheet by taking advantage of the reverse saturated absorption of 2D SnS2 and saturated absorption of 2D Bi2S3. Nonreciprocal light propagation has been achieved with different incident wavelength and a variety of incident intensities. Those characteristics make 2D Bi2S3 a potential candidate for the next generation nonreciprocal all-optical device.

The Role of Polarity in Nonplanar Semiconductor Nanostructures.

The lack of mirror symmetry in binary semiconductor compounds turns them into polar materials, where two opposite orientations of the same crystallographic direction are possible. Interestingly, their physical properties (e.g., electronic or photonic) and morphological features (e.g., shape, growth direction, and so forth) also strongly depend on the polarity. It has been observed that nanoscale materials tend to grow with a specific polarity, which can eventually be reversed for very specific growth conditions. In addition, polar-directed growth affects the defect density and topology and might induce eventually the formation of undesirable polarity inversion domains in the nanostructure, which in turn will affect the photonic and electronic final device performance. Here, we present a review on the polarity-driven growth mechanism at the nanoscale, combining our latest investigation with an overview of the available literature highlighting suitable future possibilities of polarity engineering of semiconductor nanostructures. The present study has been extended over a wide range of semiconductor compounds, covering the most commonly synthesized III-V (GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb) and II-VI (ZnO, ZnTe, CdS, CdSe, CdTe) nanowires and other free-standing nanostructures (tripods, tetrapods, belts, and membranes). This systematic study allowed us to explore the parameters that may induce polarity-dependent and polarity-driven growth mechanisms, as well as the polarity-related consequences on the physical properties of the nanostructures.