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The morphologies of different ZnO nanostructures (ZNSs) films (deposited on glass substrates) are investigated using simple and low-cost techniques. Two synthesis techniques, i.e., direct hydrothermal technique and a combination of pulsed-laser ablation under liquid and hydrothermal (PLAL-H) technique, are employed. The first technique (direct hydrothermal technique) is used to fabricate three-dimensional (3D) flower-like ZNSs and one-dimensional (1D) solid rod- along with enclosed tube-like ZNSs under different pH conditions/values. Moreover, a zero-dimensional (0D) ZnO nanoparticles (ZNPs)-based film is prepared by PLAL-H technique. The influence of tuning morphology of ZNSs films on the hydrophobic effect is examined by XRD, FE-SEM, and photoluminescence (PL). XRD patterns confirmed the polycrystalline structures of ZNSs films. FE-SEM explored the morphology transformation from 3D flower-like to 1D solid rod- and enclosed tube-like ZNSs films by varying the pH values from 10.5 to 5.7. The PL spectra revealed a higher surface area and deep-level defect density related to the ZnO morphology. Depending on the surface contact angle measurements, the hydrophobic performance of flower-like ZNSs is much superior than 1D solid rod-like, enclosed tube-like, and 0D ZNPs films. The super-hydrophobic effect of flower-like ZnO is attributed to the synergism of regular formed and higher density of ZNSs. Therefore, it is inferred that the successful controllable morphology of ZNSs film under mild deposition conditions could play a crucial role to get a superior hydrophobic behavior of ZNSs film.

Vertically oriented titanium dioxide nanotube arrays (TNTAs) decorated with NiO nanoparticles (NPs) were successfully fabricated using two-step electrochemical anodization. An ultrasound-assisted deposition method was used to homogeneously loading the NiO NPs into the TNTAs, resulting in a NiO/TNTAs junction electrode. X-ray diffraction reveals that the TNTAs and NiO/TNTAs showed anatase structures. Also, SEM images confirm that the nanotubes have a nominal length of 3.57 µm and approximately equal wall thickness and diameters; 55.51 nm and 17.64 nm, respectively. The NiO/TNTAs junction electrode exhibited high visible light photo-response that enhances the photoelectrochemical activity. Accordingly, the incident photon-to-current conversion efficiency of NiO/TNTAs was estimated to be 86.89% in comparison to the pure TNTAs whose efficiency was equal to 29.62%. In conclusion, the NiO/TNTAs junction fabricated by a simple, cost-effective, and applicable cell is a promising clean renewable source for the water-splitting applications.

This study describes the hydrothermal synthesis of cupric oxide nanoparticles (CuO NPs) using Mint extract agent. A mixture of 0.1 M copper nitrate and a mint extract was hydrothermally treated at ...

This article demonstrates the effect of substrate temperature on the pulsed-laser deposition of cadmium sulfide nanoparticles (CdS NPs). Synthesis of CdS NPs on silicon substrates was realized at a temperature range of 150–550 °C. The XRD patterns confirm that CdS NPs showed a wurtzite-hexagonal phase with crystallite size changes between 15 and 24 nm. Also, the SEM images indicate that the temperature is a crucial parameter could determine the morphology of the nanoparticles. Hence, some films exhibited aggregation and cracks causing a significant degradation in the crystalline quality. The results identify that the best quality CdS NPs correspond to an optimal temperature of 450 °C at which the nano-heterostructures could be useful for nanoelectronic applications.

Let's talk about your flaws\dots{} The authors present nondestructive examination of the crystallographic properties (including crystal size, facet shape, strain, and defects) of lone InP nanocrystals (NC) grown on Si nanostructures. This sort of three-dimensional structured imaging is of great significance in evaluating the quality of the active nanomaterials in fully processed nanoelectronic and nano-optoelectronic devices, even in an $o\phantom{\rule{0}{0ex}}p\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}r\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}d\phantom{\rule{0}{0ex}}o$ manner.

This article reports a new attempt for the bandgap formation of cadmium sulfide nanocrystals (CdS NCs) synthesized on Si(1 1 1) substrates at low temperatures: 50 and 150 °C. The influence of energy gap alteration on the optoelectronic properties was extensively considered with the aid of various tools. A wurtzite-–hexagonal structure in both CdS/Si NCs samples was confirmed by X-ray diffraction measurements. For a crystallite size around 7 nm, wider energy gaps (2.94–2.98 eV) were revealed by photoluminescence spectra. These values are in good conformity with the precise energy gaps, 2.95 eV and 3.04 eV which were estimated using a reflection-electron energy loss spectroscopy. Consequently, such expansion in the energy bandgap indicates the occurrence of a blue shift compared to the bulk CdS. Moreover, the Raman spectra show three peaks referring to the first-, second-, and third-order scattering of the longitudinal optical phonon modes. The findings demonstrate the improved crystalline quality of the sample prepared at 150 °C with no need for further thermal annealing. It is thus inferred that quantum confinement is possible in the CdS NCs prepared at low temperatures using a pulsed-laser deposition technique; thereby, they are useful for optoelectronic applications.

Pure spherical-like SnO2 and agglomerated spherical SnO2/TiO2 nanostructures (NS) films were effectively synthesized via hydrothermal route and modest combination of pulse laser ablation besides hydrothermal (PLAL-H) methods, respectively. The as-prepared samples were deposited on glass substrates at growth temperature 100 °C and characterized by FESEM, X-ray diffraction, and UV-Vis absorption and Photoluminescence (PL) measurements. Both samples exhibit a pure tetragonal rutile and anatase polycrystalline structure. The PL spectrum of pure SnO2 Ns reveals five emission peaks in UV and visible regions. In contrast, a red shift in UV emission peak was clearly observed in SnO2/TiO2 nanocomposite spectrum and disappeared all visible emission peaks. Moreover, the samples as photocatalysts films were examined under sunlight irradiation driven photodegradation of methylene blue (MB) dye. The findings exposed that the photodegradation efficiency toward MB dye at maximum irradiation time 150 min was mostly similar around 21.5 % of both as-growth films.

The growth of Al 0.85 Ga 0.15 P on GaP using gas-source molecular-beam epitaxy is investigated using in situ high-energy electron diffraction, high-resolution x-ray diffraction, atomic-force microscopy, and scanning electron microscopy. Growth temperature and phosphorus flux were varied. The 1.0-μm AlGaP films were grow on a GaP buffer layer and capped with GaP. The investigation indicates that a growth temperature of 490 °C and a cracked PH3 flux of 2.7 sccm resulted in the best AlGaP quality, while maintaining very good GaP quality.

The effect of post-growth annealing of epitaxial gallium phosphide grown on silicon substrates using gas-source molecular-beam epitaxy is described. The epitaxial layers were grown at substrate temperatures ranging from 250 to 550 °C. After optimizing the growth temperature, the prepared films were thermally annealed. Two thermal annealing methods are compared: annealing at a constant temperature and step-graded annealing, in which the temperature is raised by a constant rate per unit time. The effect of the thermal annealing on the crystal structure was studied by characterizing the epilayer using reflection high-energy electron diffraction (RHEED), X-ray diffraction (XRD) measurements, and scanning-electron microscopy (SEM). It was found that after thermal annealing, the epilayer exhibited a reconstructed RHEED pattern, and its quality was much improved.

The epitaxial integration of highly heterogeneous material systems with silicon (Si) is a central topic in (opto-)electronics owing to device applications. InP could open new avenues for the realization of novel devices such as high-mobility transistors in next-generation CMOS or efficient lasers in Si photonics circuitry. However, the InP/Si heteroepitaxy is highly challenging due to the lattice (∼8%), thermal expansion mismatch (∼84%), and the different lattice symmetries. Here, we demonstrate the growth of InP nanocrystals showing high structural quality and excellent optoelectronic properties on Si. Our CMOS-compatible innovative approach exploits the selective epitaxy of InP nanocrystals on Si nanometric seeds obtained by the opening of lattice-arranged Si nanotips embedded in a SiO2 matrix. A graphene/InP/Si-tip heterostructure was realized on obtained materials, revealing rectifying behavior and promising photodetection. This work presents a significant advance toward the monolithic integration of graphene/III-V based hybrid devices onto the mainstream Si technology platform.

The relationship between response speed of a silicon n-well/p substrate photodiode and the depletion layer width has been investigated. Variation of both the junction capacitance and the series resistance of the photodiode with the depletion layer width have been analyzed. It is shown that the contribution of the time constant and the drift time in the rise time within the depletion layer can be decreased to an optimal value (less than 1ns) just for specific value of the depletion layer width and smaller value of the diffused junction area.