Thermal lens spectroscopy, reliant on the thermal lens effect, offers a sensitive and non-invasive means for analyzing samples through their light absorption-induced refractive index changes. We aimed to enhance sensitivity using a novel differential method. This involved measuring the signal at the center point of the probe beam spot and comparing it with the signal obtained through spatial...
The effect of cascade excitations of Fermi-level electrons on the lineshape of photoemission spectra was treated by Doniach and Sunjic (DS) in 1970.1 Their derived lineshape has many issues such as its lack of integrability and failure to closely reproduce experimental data.2 We analyze this problem using a formalism rooted only in the basic quantum mechanics of resonances with a minimalist...
All inorganics halide lead perovskites have emerged as promising candidates for optoelectronic devices due to their exceptional properties, including high absorption coefficients, tunable bandgaps, and superior charge carrier mobilities. These attributes make them ideal for applications in solar cells, light-emitting diodes, and photodetectors. However, a significant challenge limiting their...
Magnesium (Mg)-based bio-alloys are used in biomedical applications such as bone fixation, cardiovascular stents, dental implants, etc. This research focuses on the mechanical and corrosion behaviour of substrates of AZ31B (Mg-Al-Zn) alloy. The thermal spray technique APPJ was used to deposit TiO2-based coating on the substrates. The microstructure, hardness and corrosion current of the...
Carbon layers of different thicknesses were evaluated as protective layers on titanium to prevent metal oxidation. Titanium films (99.95% purity) 100 nm thick were deposited on Si (100) in a high-vacuum magnetron sputtering system with a working pressure of 5 mTorr. A Pinnacle source with 150 Watts and 20 kHz was used. The target contained surface oxide which was deposited on the substrate....
Exploration of proposals to address environmental issues, such as water decontamination, is a topic of significant interest. Advanced oxidation processes, such as heterogeneous photocatalysis, present feasible options for degrading organic pollutants in water. Thus, there has been a recent surge in research efforts focused on identifying ideal thin film photocatalysts. This study aimed to...
In this work we will show the fit of some of the transition metals of the sixth period, using the Double Lorentzian line shape, specifically the 4f orbitals with their two branches 7/2 and 5/2 and the background used will be the Shirley-type background (SVSC). The fits were performed with the AAnalyzer© software and shared on the web at the https://xpsoasis.org/ platform. The use of the DL...
Aluminum, a reactive metal, rapidly reacts with oxygen to form a protective aluminum oxide layer. It has three electrons in its valence shell, allowing it to form oxidation states of Al+1 and Al+2, with Al+3 being the most stable oxidation state.
Film deposition of metallic aluminum (99.99% pure aluminum pellets from Sigma Aldrich) through thermal sublimation under ultra-high vacuum...
Non-collinear antiferromagnets have attracted much attention due to the possibility to exhibit anomalous and topological Hall effects. The D019-Mn3X (X = Ga, Ge and Sn) compounds, with hexagonal crystal structure (space group No. 194) and kagome spin structure in the (0001) plane, are candidates to show these effects, which could serve as the reading mechanism in future non-volatile magnetic...
Based on the viability of the method to grow other 1111 family iron-based compound polycrystalline superconductor thin films by MOCVD and exitu diffusion processes, in this work, we report studies details of the synthesis of the SmFe1-xCoxO thins films by MOCVD and exitu diffusion processes. The cobalt (Co) percentage is varied in the films, and different thermal treatments are explored to...
Chikungunya fever is a zoonotic disease caused by the Chikungunya virus with a fatality rate of 1 death per 1,000 infected patients. The main symptoms of this disease are fever, muscle and joint pain, in most cases, these symptoms persist for two weeks; however, it is possible to develop a chronic form of Chikungunya disease where comorbidities that lead to death may develop. The introduction...
The XPS equipment at the Laboratorio de Procesamiento y Caracterización de Nanopelículas (LPCN) at Cinvestav-Querétaro, is one of the oldest XPS pieces of equipment that still provides high-quality data. Besides basic issues such as keeping it clean and employing a low base pressure (in the 10-10 Torr range), two of the reasons that have kept this equipment competitive are the following:
1)...
X-ray Photoelectron Spectroscopy (XPS) is renowned for its acute sensitivity to surface characteristics, which enables detailed quantitative analysis of the elemental and chemical state of surface layers up to approximately 10 nanometers deep. XPS is extensively employed across various industrial and academic settings due to the widespread availability of commercial systems that facilitate...
Cu and Ni are metallic elements relatively abundant with important applications by their own. There are reports of catalytic applications for Cu-Ni bimetallic films and copper oxides and nickel oxides are semiconductor compounds. CuO is a p-type semiconductor with a narrow bandgap of approximately 1.3 eV to 2.1 eV. NiO is also a p-type is a ferroelectric semiconductor with direct allowed...
Transparent conductive oxides (TCOs) have garnered significant attention in scientific and technological circles due to their unique optoelectronic characteristics: high electrical conductivity coupled with optical transparency. The quest for eco-friendly materials in TCO development remains ongoing, with zinc oxide (ZnO) standing out as a promising candidate. Through supervalent doping with...
The main peak of most of the p, d, and f X-ray photoemission spectra from transition metals exhibit an asymmetry that extends towards the high binding energy side. This asymmetry is observed also in some oxides. The asymmetry in peaks of photoemission spectra arises from a non-symmetric distribution of the final states of the core hole. These states can be related to multiplet...
Hafnium-based materials have been crucial in electronic devices in the last few years. Current challenges are species migration and the growth of an interfacial layer (mainly after annealing), both hindering device performance. Nitridation is a possible solution. ARXPS provides non-destructive depth profiling information, offering valuable insights to understand the nitridation mechanism. ...
