This paper shows how a simple modification of the electrodes in a basic commercial plasma cleaner allowed the oxidation of compound semiconductors (GaAs) and Si at room temperature. We explained the oxidation of the semiconductor surface by the participation of aluminum atoms evaporated from the electrode surface in the discharge, which resulting in additional ultraviolet (UV) radiation from the plasma. The UV radiation not only increases the decomposition of oxygen molecules adsorbed on the surface but also results in photoionization of GaAs with the formation of Ga and As ions at the oxide–GaAs interface. In addition to obtaining oxides on semiconductor surfaces, the modified device proved to be an effective tool for etching amorphous carbon films.

This study employed time-of-flight secondary ion mass spectrometry (TOF-SIMS) to investigate degradation pathways at the nanoscale, utilizing its capacity for in-depth chemical and structural analysis through various methods, including depth profiling and 3D analysis. A key focus is the matrix effect in ToF-SIMS, which alters secondary ion yields based on the sample matrix composition, influencing species identification and quantification. We show that this effect can be used to enhance the resolution of ToF-SIMS beyond its traditional limits, allowing for detailed imaging of the degradation process. Our findings indicate that the initial formation of PbI2 phases, a crucial step in the degradation pathway triggered by environmental factors, can be traced and visualized. By investigating the sputtering yields and secondary ion formation, we reveal the nonlinear sputtering regimes present in MAPI, contributing to our understanding of the mechanisms driving perovskite degradation. The application of this enhanced analytical technique paves the way for improved degradation studies.

Mechanosynthesis, particularly through high-energy ball milling, offers a potent method for the fabrication of nanohybrids. This study explores the characterization of TiO 2 and graphene oxide (GO) nanohybrids, focusing on their optical and electrical properties, as well as their photocatalytic performance. Optical measurements showed a reduction in the bandgap from ≈3.27 eV in pristine TiO 2 to ≈3.02 eV in milled TiO 2 , while electrical conductivity increased from 5.59 × 10 -9 to 2.48 × 10 -8 S/cm. Despite these improvements, the addition of GO did not significantly impact the bandgap or electrical properties of the nanohybrids. Photocatalytic experiments using methylene blue (MB) under visible light irradiation demonstrated a dye degradation of ≈30-32% in all hybrid samples, indicating consistent photocatalytic activity regardless of GO oxidation degrees.

This work is devoted to the study of the formation of periodic relief on the InP surface during ion sputtering by bismuth ions with an energy of 30 keV and an angle of incidence of 45° respect to normal incidence. We compared the reliefs formed by sputtering with atomic and cluster bismuth ions, as well as the relief appearing on the surface of the sample irradiated at elevated temperature (290 °C). Three different types of reliefs were found: surface waves with nanodots on the surface “waves”, nanodots with uniform distribution and relief in the form of columnar micro crystallites during sputtering of a heated target. With increasing irradiation dose, insignificant changes in characteristic surface dimensions were observed for all three reliefs. Based on the nonlinear character of surface sputtering (“thermal spot” sputtering mode), we described the formation of relief in the form of nano-dots and in the form of micro crystallites as a result of local melting areas formation and subsequent solidification (crystallization) on the target surface. Regarding wave relief, in our opinion, an adequate physical description is given by a model based on the stress driven dynamics of ion irradiated surface.

Metal-halide perovskites, known for their remarkable photovoltaic performance and ease of production, have garnered global attention in material science. Addressing scalability requires tackling the technology’s primary challenge: instability. Crucial insights into the complex chemistry of these materials are imperative for progress. The present study focused on well-known perovskites, namely CsPbI 3 , CH 3 NH 3 PbI 3 and HC(NH 2 ) 2 PbI 3 . Through both cohesive energy and ICOHP analysis, the chemical bonding of these compounds. Additionally, a comparative evaluation of the functionals of TPSS, revTPSS, HCTH/407, and PBE was made through bandgap determination. The key findings of this study were: i) having confirmed the predominantly ionic nature of lead halide interactions; ii) having pointed out the predominantly covalent nature of the molecules’ constituents binding; iii) having found that the strongest hydrogen bonds are formed by methylammonium; and iv) having nourished the utility of the TPSS meta-GGA functional in calculating the band gap of organic–inorganic perovskites. The results presented here could be important to the understanding and description of metal halide perovskite materials.

In this study are presented Cu 2 O thin films by microwave-assisted chemical bath deposition. The effect of temperature and time is studied on the film's structural, optical, and electrical properties. It was found that conductivity presents an opposite behavior when increasing time deposition at 65 and 70 ºC, promoting a decrease for films deposited at 65 ºC and an increase for films deposited at 70 ºC. This opposite behavior is correlated with structural defects (Urbach Energy), since these are reduced during the deposit carried out at 65 ºC and increase during the process carried out at 70 ºC. This can be explained by the fact that in the process at 65 ºC, the growth of the film thickness is continuous, that is, it increases more or less uniformly all the time, causing an increase in the crystallite and in the particles observed in SEM with a more or less well-defined morphology. While in the case of films at 70 ºC, the thickness growth after 30 minutes of deposit is minimal, which generates changes in the structure of the deposited film, for example, a deterioration in the morphology of the particles is observed, these changes encourage an increase in structural disorder as well as a decrease in crystallite size.

The goal of this work is to study the effect of annealing temperature T a on the properties of CH 3 NH 3 PbI 3 (MAPI) thin films deposited on glass substrate through structural, compositional, and optical characterization. The films were obtained by one-step deposition method in which an anti-solvent drip was implemented with some delay during spin coating of the precursor mixture, followed by thermal annealing to promote solvent evaporation and rapid crystallization of the film. Properties of the perovskite film after thermal annealing were characterized by different analytical methods. The morphology and roughness of the films were studied by scanning electron microscopy and atomic force microscopy. The crystalline phase was characterized by X-ray diffraction. The optical properties were also determined by UV–Vis spectroscopy. Finally, the elemental composition was analyzed by secondary ion mass spectroscopy. In the temperature range of 100–160 °C, variable average grain diameters between ~ 200 and ~ 500 nm were obtained. However, higher post-deposition thermal annealing temperatures produce clusters of PbI 2 between CH 3 NH 3 PbI 3 grain boundaries. XRD measurements showed a decrease in MAPI crystallite size and an increase in PbI 2 crystallite size and amount with increasing annealing temperature. In addition, higher T a results in a modification of the absorption/reflectance spectra and a red shift of an optical band gap. The results of this study can be useful to produce thin films of MAPI with tunable optical and electronic properties for optimizing the performance of photovoltaic devices.

In this work graphene oxides (GOs) were synthesized by the tour method. The oxidation degree of GOs was varied using different dosages of KMnO4 during the synthesis (0.5, 3, and 6 g). By X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), we quantitatively determined the oxidation degree of the materials (4.1, 49.5, and 53.9%). In addition, bandgaps ranging from 0.8 to 2.18 eV were calculated, thus verifying the dependence of the bandgap on the oxidation degree. With this work, we demonstrate that by the tour method it is possible to synthesize and control the oxidation degree in the GOs, in such a way that we can change the nature of the material from semimetallic to semiconducting with the modification of its bandgap. The study of our GOs was complemented with FT-IR spectroscopy and Raman spectroscopy.

Sequential deposition of Cu2O on FTO substrates was performed by chemical bath deposition to increase the thickness of the films. The variation of structural, optical, morphological, and electrochemical properties was studied as the number of deposits increased. The increase of thickness promotes an increase in the crystallite size and the lattice constant a, as well as a shift in the region of the absorption of light towards lower energies, reducing the band gap and the transmittance slightly. Also, it was estimated a change in the preferential orientation from the plane (111) to (200), caused a decrease in the structural disorder (Urbach energy) as a consequence of reducing the conductivity. On the other hand, during the electrochemical characterization a p-type behavior was observed in all the films, and as the thickness increased a shift towards more positive flat band potential values and a decrease in the carrier concentration was observed, which is the result of the decrease in structural disorder. The photocurrent measurements showed that the best performances were by the thinnest and the thickest films because some are the most conductive and the others absorb more light.

The influence of the composition of silicate glass substrates on the properties of MAPI (CH 3 NH 3 PbI 3 ) films with a 1:1:1 % mol ratio of MAI:PbI 2 :DMSO, deposited by Spin-Coating at 4000 rpm for 30 seconds, was studied. X-ray diffraction suggested the presence of the tetragonal phase and a secondary PbI 2 phase. By SEM and AFM grain sizes between 100 and 250 nm with an average roughness between 6-15 nm were observed. Different degrees of compaction and porosity between grains were also observed in the films, depending on the substrate used.