Microstructure and dispersive optical parameters of iron films deposited by the thermal evaporation method

Amorphous carbon-based coatings deposited on copper substrates by magnetron sputtering at different target-to-substrate distances were investigated. Films deposited at short distances as 2 cm presented the best results in terms of morphology, density, and resistivity. Ultraviolet near-infrared range spectrometry measurements determined total reflectance and ellipsometry, extinction coefficient, refraction index, and pseudo bandgap. Amorphous carbon films of 150 nm deposited at 2 cm reduced the total reflectance by up to 60 ± 5% in the near-infra-red range when compared to pure copper films. The addition of Fe*boosts the absorption of the coating reducing the total reflectance by up to 70 ± 5% in near-infrared. (Fe*: deposited from stainless-steel target used in direct-current magnetron sputtering). Also, it reduces the electrical resistivity by a factor of 100 compared to that of pure amorphous carbon films. The reduction in total reflectance induced by the presence of the amorphous carbon-based films on copper depends, as expected, on light penetration depth and the absorption coefficient.

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“…This could explain the higher values of n and k for a-C:Fe* films and the tendency observed in Fig. 10b) [61,62].…”

Section: Ellipsometry Measurementsmentioning

confidence: 62%

“…10 it is seen that n varies from 2 to 2.75 for a-C:Fe* and a-C. Concerning iron, n and k for bulk or thin films are higher than for pure sputtered carbon [60,61], where n reaches values higher than 3 at 850 nm [61]. This could explain the higher values of n and k for a-C:Fe* films and the tendency observed in Fig.…”

Section: Ellipsometry Measurementsmentioning

confidence: 72%

Low resistivity amorphous carbon-based thin films employed as anti-reflective coatings on copper

et al. 2020

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“…On the other hand, the influence on surface morphology and topography was smaller when varying the RF source power and target-to-substrate distances. The AFM and SEM results indicated a predominantly Volmer-Weber (3D island) growth mode, with the interaction between the adatoms being greater that their interaction with the substrate, growth mode generally observed for metals deposited at low temperatures [ 31 , 52 , 53 ].…”

Section: Resultsmentioning

confidence: 99%

Nanoscale Control of Structure and Composition for Nanocrystalline Fe Thin Films Grown by Oblique Angle RF Sputtering

et al. 2022

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The use of Fe films as multi-element targets in space radiation experiments with high-intensity ultrashort laser pulses requires a surface structure that can enhance the laser energy absorption on target, as well as a low concentration and uniform distribution of light element contaminants within the films. In this paper, (110) preferred orientation nanocrystalline Fe thin films with controlled morphology and composition were grown on (100)-oriented Si substrates by oblique angle RF magnetron sputtering, at room temperature. The evolution of films key-parameters, crucial for space-like radiation experiments with organic material, such as nanostructure, morphology, topography, and elemental composition with varying RF source power, deposition pressure, and target to substrate distance is thoroughly discussed. A selection of complementary techniques was used in order to better understand this interdependence, namely X-ray Diffraction, Atomic Force Microscopy, Scanning and Transmission Electron Microscopy, Energy Dispersive X-ray Spectroscopy and Non-Rutherford Backscattering Spectroscopy. The films featured a nanocrystalline, tilted nanocolumn structure, with crystallite size in the (110)-growth direction in the 15–25 nm range, average island size in the 20–50 nm range, and the degree of polycrystallinity determined mainly by the shortest target-to-substrate distance (10 cm) and highest deposition pressure (10−2 mbar Ar). Oxygen concentration (as impurity) into the bulk of the films as low as 1 at. %, with uniform depth distribution, was achieved for the lowest deposition pressures of (1–3) × 10−3 mbar Ar, combined with highest used values for the RF source power of 125–150 W. The results show that the growth process of the Fe thin film is strongly dependent mainly on the deposition pressure, with the film morphology influenced by nucleation and growth kinetics. Due to better control of film topography and uniform distribution of oxygen, such films can be successfully used as free-standing targets for high repetition rate experiments with high power lasers to produce Fe ion beams with a broad energy spectrum.

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Microstructure and dispersive optical parameters of iron films deposited by the thermal evaporation method

Cited by 2 publications

References 36 publications

Low resistivity amorphous carbon-based thin films employed as anti-reflective coatings on copper

Low resistivity amorphous carbon-based thin films employed as anti-reflective coatings on copper

Nanoscale Control of Structure and Composition for Nanocrystalline Fe Thin Films Grown by Oblique Angle RF Sputtering

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