Tailoring Properties of Hafnium Nitride Thin Film via Reactive Gas-Timing RF Magnetron Sputtering for Surface Enhanced-Raman Scattering Substrates

This study successfully demonstrated the tailoring properties of hafnium nitride (HfN) thin films via reactive gas-timing (RGT) RF magnetron sputtering for surface-enhanced Raman spectroscopy (SERS) substrate applications. The optimal RGT sputtering condition was investigated by varying the duration time of the argon and nitrogen gas sequence. The RGT technique formed thin films with a grain size of approximately 15 nm. Additionally, the atomic ratios of nitrogen and hafnium can be controlled between 0.24 and 0.28, which is greater than the conventional technique, resulting in a high absorbance in the long wavelength region. Moreover, the HfN thin film exhibited a high Raman signal intensity with an EF of 8.5 × 104 to methylene blue molecules and was capable of being reused five times. A superior performance of HfN as a SERS substrate can be attributed to its tailored grain size and chemical composition, which results in an increase in the hot spot effect. These results demonstrate that the RGT technique is a viable method for fabricating HfN thin films with controlled properties at room temperature, which makes them an attractive material for SERS and other plasmonic applications.

ORGAN WEIGHT INDICES AS INDICATORS FOR ESTIMATING THE EXPERIMENTAL EFFECT OF METAL NITRIDE COATED IMPLANTS ON ANIMAL ORGANISMS

The obtained results confirm the safety of steel 12ХI8Н9Т implants and titanium plus hafnium nitride TiN+NHf coated steel 12ХI8Н9Т implants. Experimental data analysis shows the toxic properties of copper supported by the earlier research on blood morphology of lab rats.

Mechanical and Structural Behavior of HfN Thin Films Deposited by Direct Current and Mid-Frequency Magnetron Sputtering

Nanocrystalline HfN thin films were deposited onto silicon substrates with direct current magnetron sputtering (dcMS) and mid-frequency magnetron sputtering (mfMS) by using hafnium metallic target with 3-inch diameter and 99.9% purity in argon/nitrogen atmosphere, under 4 different pulse frequencies and duty cycles. In order to evaluate the structural, morphological and mechanical properties, we used X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), nanoindentation tests. X-ray diffraction patterns show that films sputtered in dcMS mode have a mixed δ-HfN and HfN0.4 phases, whereas mfMS favor a single δ-HfN phase. mfMS leads to films with the higher mechanical hardness and smaller surface roughness than those of films deposited by dcMS. Hafnium nitride films with a single δ-HfN phase show the highest hardness values of 24.5 GPa while those of mixed δ-HfN and HfN0.4 phases show the lowest 18.3 GPa. In summary, the sputtering technique has a crucial role on the properties of the film and can be suitable used to adjust the structure and hardness of HfN films.

Low Resistivity Hafnium Nitride Thin Films Deposited by Inductively Coupled Plasma Assisted Magnetron Sputtering in Microelectronics

Hafnium nitride (HfN) thin films with low electrical resistivity were obtained by inductively coupled plasma assisted magnetron sputtering as a function of ICP power. Microstructural, crystallographic and sheet resistance characterizations of HfN films were performed by field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), X-ray diffraction (XRD) and 4 point probe method. The results show that ICP has significant effects on coating’s microstructure, structural and electrical properties of HfN films. With an increase in ICP power, thin film microstructure evolved from a porous columnar structure to a highly dense one. HfN thin films with different crystal structure and phases were obtained as a function of ICP power. The minimum resistivity of 125 µΩ-cm, the smoothest surface morphology with Ra roughness of 5.9 nm were obtained for the HfN films deposited at ICP power of 200 W.

Computational investigation of the plasmonic properties of TiN, ZrN, and HfN nanoparticles: The role of particle size, medium, and surface oxidation

Group 4 transition metal nitride (TMN) nanoparticles (NPs) display strong plasmonic responses in the visible and near-infrared regimes, exhibit high melting points and significant chemical stability and thus are potential earth-abundant alternatives to Au and Ag based plasmonic applications. However, a detailed understanding of the relationship between TMN NP physical properties and plasmonic response is required to maximize their utility. In this study, the localized surface plasmon resonance (LSPR) frequency, bandwidth, and extinction of titanium nitride (TiN), zirconium nitride (ZrN), and hafnium nitride (HfN) NPs were examined as a function of the particle size, surface oxidation, and refractive index of the surrounding medium using finite element method (FEM). A linear redshift in the LSPR frequency and a linear increase in the associated full width at half maximum (FWHM) was observed with increasing the particle size, oxidation layer thickness, and medium refractive index. We show that the effect of surface oxidation on plasmonic properties of TMN NPs is strongly size-dependent with a significant LSPR redshift, intensity reduction, and broadening in small NPs compared to larger NPs. Furthermore, the performance and efficiency of HfN, ZrN, TiN as well as Au NPs for a narrowband application - photothermal therapy (PTT), and a broadband application - solar energy conversion, was investigated in detail. The results indicate that narrowband and broadband photothermal performance of NPs strongly depend on the particle size, surface properties and in case of narrowband absorption, excitation wavelength.