Bonding structure and hydrogen content in silicon nitride thin films deposited by the electron cyclotron resonance plasma method

The bonding structure and hydrogen content of amorphous hydrogenated silicon nitride (a-SiNx:H) thin films have been investigated by infrared spectroscopy and ion beam techniques. Electron cyclotron resonance plasma enhanced chemical vapor deposition was used to produce these films under different values of gas flow ratio, deposition temperature, and microwave power. The amount of bonded hydrogen was calculated from the N-H and Si-H infrared absorption bands. An increase of the SiH4 partial pressure during deposition was found to have the same effect on the H content as an increase of the substrate temperature: both cause a decrease of the N-H bond density and an increase in the number of Si-H bonds. This is explained by a competitive process in the formation of N-H and Si-H bonds during the growth of the film, whereby Si-H bonds are favored at the expense of N-H bonds when either the SiH4 flow or the substrate temperature are increased. Such tendency to chemical order is compared with previous results in which the same behavior was induced by thermal annealing or ion beam bombardment

Optical and photoconductive properties of indium sulfide fluoride thin films

This work reports on transparent semiconducting indium sulfide fluoride (ISF) thin-films exhibiting high sensitivity to ultraviolet radiation. The films were deposited on fused silica and silicon substrates using a radiofrequency plasma-enhanced reactive thermal evaporation system. The deposition was performed evaporating pure indium in SF6 plasma at a substrate temperature of 423 K. Rutherford backscattering measurements were used to determine the chemical composition of the films deposited on silicon substrates. The surface morphology was studied using scanning electron microscopy technique. The film characterization includes electrical, optical, and photoconductivity measurements. The synthesized compound is highly-resistive (similar to 700 M Omega-cm at 300 K) and exhibits an evident semiconducting behavior. The activation energy of 0.88 eV is deduced from the temperature dependence of electrical resistivity. The indirect band energy gap of 2.8 eV is determined from transmittance spectra of the ISF films. The photoconductivity band is centered at 345 nm wavelength. The photoconductivity spectrum also shows the Urbach tail with a characteristic energy of 166 meV. ISF is a promising candidate for a buffer layer in chalcogenide-based solar cells.info:eu-repo/semantics/publishedVersio

Me-Doped Ti–Me intermetallic thin films used for dry biopotential electrodes: a comparative case study

In a new era for digital health, dry electrodes for biopotential measurement enable the monitoring of essential vital functions outside of specialized healthcare centers. In this paper, a new type of nanostructured titanium-based thin film is proposed, revealing improved biopotential sensing performance and overcoming several of the limitations of conventional gel-based electrodes such as reusability, durability, biocompatibility, and comfort. The thin films were deposited on stainless steel (SS) discs and polyurethane (PU) substrates to be used as dry electrodes, for non-invasive monitoring of body surface biopotentials. Four different Ti–Me (Me = Al, Cu, Ag, or Au) metallic binary systems were prepared by magnetron sputtering. The morphology of the resulting Ti–Me systems was found to be dependent on the chemical composition of the films, specifically on the type and amount of Me. The existence of crystalline intermetallic phases or glassy amorphous structures also revealed a strong influence on the morphological features developed by the different systems. The electrodes were tested in an in-vivo study on 20 volunteers during sports activity, allowing study of the application-specific characteristics of the dry electrodes, based on Ti–Me intermetallic thin films, and evaluation of the impact of the electrode–skin impedance on biopotential sensing. The electrode–skin impedance results support the reusability and the high degree of reliability of the Ti–Me dry electrodes. The Ti–Al films revealed the least performance as biopotential electrodes, while the Ti–Au system provided excellent results very close to the Ag/AgCl reference electrodes.This work was supported by the European Regional Development Fund (ERDF) and by the European Union’s Seventh Framework Programme, grant number 610950; through the Operational Programme for Competitiveness and Internationalization (COMPETE 2020), under Portugal 2020 in the framework of the NanoStim, grant number POCI-01-0247-FEDER-045908, and NanoID, grant number NORTE-01-0247-FEDER-046985 Projects; and the Free State of Thuringia grant number 2018 IZN 004

The 2021 IAEA software intercomparison for k₀-INAA

In order to establish the variation between results in mass fractions due to software implementation, as measured by the k0-method for INAA, the IAEA has organized a software intercomparison. A complete set of test spectra and associated information was assembled. Efficiency curves, neutron spectrum parameters, correction factors and mass fractions were calculated with the participating programs (k0-IPEN, k0-INRIM, k0-DALAT, k0-IAEA and KayWin) using identical peak areas. In this paper, we report on the observed discrepancies, causes, remedies and future software developments. The test data, as well as intermediate results and observed mass fractions of the certified reference material BCR-320R “channel sediment” are available through the IAEA on request. The variations in concentrations attributed to differences between the programs were initially found to be 5.6 and 7.9%, for certified and uncertified concentrations, respectively. After the certified concentrations had been made available to the participants and they had been allowed to improve their programs, the variations found were 2.7 and 3.4%, respectively. The main identified remaining causes of variation are differences in the procedures used for detector efficiency characterisation and neutron spectrum parameter determination.RID/KEWO/Kwaliteitszorg-IM