Nitrogen Ion Irradiation Research Articles

Effect of 60 MeV nitrogen ion irradiation on few layer WSe2 nanosystems

This study explores the impact of 60 MeV N5+ ion irradiation on few layer WSe2 systems. The structural analysis exhibit an anomalous variation in crystallite size with increasing grain growth after irradiation. Raman spectroscopy study reveals increased disorder, enhanced intensities of prominent modes, and an eight-fold rise in AFM-measured roughness from 27.2 nm to 212.6 nm. HR-TEM shows voids in nanosheets post-irradiation. In addition, DFT calculations on monolayer with vacancy clusters shows modification of WSe2 bandgap from 1.48 eV to 0.37 eV. Interrelated structural, morphological and electronic structure calculations would provide useful insights upon controlled radiation exposure.

Enhancing photodetector performance of MoS2 thin films by nitrogen ion irradiation

In this work, MoS2 thin films were grown on a Si substrate using RF sputtering, and subsequently subjected to nitrogen ion irradiation with varying ion fluence. The Raman spectroscopy observed the oxygen doping into MoS2 lattice and induced shift in E2g and A1g vibration modes, along with a decrease in the interdefect distance (LD) after ion irradiation. The evolution of oxygen into MoS2 sample after ion irradiation was confirmed by XPS. The incorporation of oxygen in the MoS2 is due to the bond breaking of the surface layers of the material due to ion irradiation, which creates dangling bonds. These bonds in the MoS2 are more reactive with the oxygen and lead to the formation of MoOx species on the surface of the material. The Field Emission Scanning Electron Microscopy (FESEM) provides the morphological study of post-irradiation samples. As ion fluence increases, the optical bandgap decreases from 1.46 eV to 1.33 eV. Using current-voltage (I–V) characteristics, the electrical properties of the irradiated films were characterized, along with photodetector measurements. This combined analysis provided a comprehensive understanding of the film's electrical behaviour, shedding light on their post-irradiation performance. Our results demonstrate that due to oxygen doped into MoS2/Si thin film significantly affects the barrier height, ideality factor, and carrier concentration in I–V characteristics. Taking silicon-based and n-type MoS2 heterojunction photodetectors, its photoresponsivity can reach ∼14.7 mA/W at 7.19 × 1016 ion-cm−2 ion fluence. Our findings provide insights into the tunability of the electrical properties of MoS2/Si thin films through ion irradiation, which has implications for the development of novel electronic and optoelectronic devices based on MoS2/Si thin film.

The effect of nickel additive and ion irradiation on the structural and optical properties of lithium borate glasses

The study investigates the impact of nickel oxide (NiO) doping (0%, 0.1%, 0.2%, and 0.3% wt%) on the glass composition 85B2O3-15Li2O using the melt quenching technique. Both X-ray diffraction (XRD) and FTIR confirm the amorphous nature and functional groups. Density, molar volume, average boron separation, ion concentration, interionic distance, polaron radius,. UV-visible absorption (200–1100 nm) was also recorded before and after nitrogen ion beam irradiation (fluence: 8x1017 and 16x1017 ion/cm2). Results indicate a decrease in the optical energy gap (Eoptical gap) and an increase in Urbach’s energy (EU) with higher NiO content, especially post-irradiation. Nitrogen ion irradiation at higher doses (16x1017 ion/cm2) induces more significant effects, attributed to increased non-bridging oxygen species (NBOs) formation and finally dielectric parameters were measured from 100 Hz to 100 kHz. Overall, the ability to tailor borate glass properties via nitrogen ion irradiation holds promise for diverse technological applications in optoelectronics, photonics, sensors, and radiationdetection

Nitrogen-ion-irradiated defective tin oxyhydroxide nanoparticle anode for ultrafast and highly stable lithium-ion storage

High-performance lithium-ion batteries require high energy density, long cycle life, and fast (dis)chargeability. Despite several accomplishments in increasing capacity under normal operation, maintaining high capacity under fast charging and discharging remains a challenge. To achieve such performance, we have applied nitrogen-ion (N+) irradiation to an anode material comprising tin oxyhydroxide nanoparticles (Sn6O4(OH)4 NPs) active material, carbon black conducting agent, and polyvinylidene fluoride (PVDF) binder. Sn6O4(OH)4 NPs have high capacity and fair rate capability due to their layered structure with a large interlayer spacing of 0.455 nm and a small particle size of < 5 nm. N+ irradiation induces multiple defects including implanted N+ and oxygen vacancies in the anode material. The defects provide more Li-ion active sites in the Sn6O4(OH)4 NPs and lead to amorphization of carbon black as well as increasing the conductivities of Sn6O4(OH)4 NPs. Additionally, N+ irradiation brings about cross-linking of PVDF, enhancing the binding property. As a consequence, the N+-irradiated anode shows significantly improved performance: a capacity maintains 2306 mA h g−1 after 500 cycles at 0.5C and 1053 mA h g−1 after 300 cycles at 5C. Moreover, the anode exhibits outstanding rate capability even under ultrahigh-rate operation: 65.1 % capacity retention at 50C.

Augmented electrochemical properties of manganese oxide nanorods on low energy nitrogen ion irradiation

For the development of versatile and high-performance storage devices, nanorods-based supercapacitors hold great promise due to their high energy density per unit volume and their resilience in the face of high mechanical stress. In this study, we demonstrated how to increase charge storage capacity by using an ion beam to join manganese oxide nanorods on a massive scale, thereby creating surface defects. Hydrothermally synthesized Mn3O4 nanorods were spin-coated on a silicon wafer and subjected to low energy (5 keV) N+ ion-beam at varying ion fluences before undergoing extensive electrochemical characterizations to verify their charge storage performance. At a mass normalized current of 10 A/g, the areal capacitance for pristine and irradiated Mn3O4 nanorods is 45 mF/cm2 and 132 mF/cm2. Hence, irradiated Mn3O4 nanorods were found to have better charge storage performance than their untreated counterparts. Insights into the improved charge-storage performance of irradiated nanorods are made clear by the detailed experimental findings. The irradiated sample further retains 90% of its initial capacitance for more than 5000 cycles of measurements. The enhanced areal capacitance performance after irradiation is due to the oxygen vacancy supported by TRI3DYN simulations. The high charge storage performance of the irradiated samples can be attributed to several factors, including the induced oxygen vacancy and improved surface area. This research adds to the growing body of evidence that ion beam irradiation can be used to fine-tune the supercapacitor electrode's surface area, conductivity, and storage capacity.

Cluster formation by the precise joining of iron oxide nanoparticles on low energy nitrogen ion irradiation

In this work, we have studied low-energy (5 keV) nitrogen ion-induced modification of the surface of iron oxide nanoparticles. The iron oxide nanoparticles were spin-coated on a silicon substrate. The thin films of iron oxide nanoparticles were irradiated at two different ion fluences of 1 × 1016 and 3 × 1016 ions cm−2, respectively. At a fluence of 1 × 1016 ions cm−2, the nanoparticles incline to join with each other forming small clusters which can be attributable due to Ostwald ripening because of the ion-induced defects. At higher fluence of 3 × 1016 ions cm−2, large nanoclusters are formed due to coalescence. We have investigated the morphological and structural properties of both the pristine and altered surface in detail to understand the cluster formation. We anticipate that such reformed surfaces can be beneficial to enhance the surface plasmon resonance.

Investigation of the effect of nitrogen ion irradiation on the lithium surface condition

A comparison of the surface of solid lithium in the atomically pure state, after contact with oxygen, nitrogen and after irradiation with N+ ions with an energy of 0.6 keV at a current density of 2 μA/mm2 was carried out. The analysis of surface characteristics was carried out using electron Auger spectroscopy. To obtain an atomically pure surface, low-energy electron bombardment was used. It is shown that the contact of an atomically pure Li surface with oxygen leads to the formation of lithium oxide, and with nitrogen with a partial pressure of 10-6 Pa, lithium oxide and oxynitride in a mixture with free lithium atoms. Irradiation of lithium with nitrogen ions leads to the formation of the surface compound Li3N. It is noted that the resulting compound is unstable in ultrahigh vacuum and eventually decays to form lithium oxide due to interaction with the residual oxygen of the spectrometer chamber. Keywords: lithium, vacuum, ions, electrons, surface.

On issue of selecting of ion implantation dose for activating of surface layer of alloy steel parts before nitriding

The article discusses the method of selecting ion irradiation doses for high-energy activation of the surface layer of alloy steel parts before nitriding. A criterion is proposed for optimizing the radiation dose of implanted ions from the strength limit of plate samples with a thickness commensurate with the thickness of the nitrided layer at implantation energies that ensure their end-to-end activation. The results of tests for rupture of plate samples with a through nitrided layer are presented. The results of comparative wear tests of samples made of alloy steels with nitrided layers used for the manufacture of machine parts operating under conditions of wear friction are presented. It is shown that the use of the method of selecting the dose of nitrogen ion irradiation with high-energy activation of the surface of samples made of alloy steels 40X and 40HN, allows to increase their wear resistance by approximately 1.3—1.4 times.

Influence of nitrogen ion on radiation shielding properties of Lead Doped Cadmium Ferrite Nanoparticles

The effect of 5 keV, 200 μm/cm2 nitrogen ion irradiation on the structural, surface morphology, and shielding of lead doped cadmium ferrite nanocomposites are studied using XRD, SEM, TEM and EDX technics. The crystal size decreases after ion irradiation and EDX was used to obtain details of the doped nitrogen atom in the sample. The shielding characteristics of irradiated and unirradiated spinel ferrite samples are investigated for gamma ray radiation shielding using 60Co and 137Cs sources and an HPGe detector. Linear attenuation (μ, cm−1) Mass attenuation coefficients (μ/ρ, cm2/g), and half-value layer (HVL, cm) were determined at different photon energies, and have been measured experimentally and modelled using the MicroShield program. Good agreement was obtained between experimental and modeling results for the irradiated samples. Neutron macroscopic cross section was also calculated for the prepared samples before and after nitrogen ion irradiation. Results showed that the mass attenuation coefficient and other shielding parameters depend upon the nitrogen ion beam irradiation, and highly increased shielding properties nearly twice it's value of unirradiated samples against gamma rays as well as fast neutrons.

Effect of low energy nitrogen ion irradiation on MoO3 films

In the present work, Molybdenum trioxide (MoO3) thin films were deposited by the electrophoretic deposition (EPD) method. Low energy ion irradiation was used to alter the materials properties of MoO3 films. Ion irradiation was carried out at a constant ion fluence of 2.16 x 1016 ions/cm2 for energies varying from 10 keV to 40 keV. The X-ray diffraction (XRD) and Raman spectroscopy revealed the orthorhombic α-MoO3 phase. The optical band gap was observed to change from 3.73 eV to 3.08 eV in a controlled manner due to ion irradiation. Morphology of nanobelt-like structures was seen at the highest energy of ion irradiated films. Atomic force microscopy (AFM) revealed a decrease in the surface roughness with an increase in irradiated ion energy. All results are in corroboration with each other and comprehend the process of tailoring the material properties of MoO3 thin film due to low energy ion irradiation. These tailored properties could be useful for electronic or optical device applications.

Energy-Carrying Nitrogen Ion Irradiation Induced Dislocation-Rich Bioi Nanosheets Toward Nir-Triggered Bactericidal Activity

Energy-Carrying Nitrogen Ion Irradiation Induced Dislocation-Rich Bioi Nanosheets Toward Nir-Triggered Bactericidal Activity

Fabrication and Surface Deformation of Boron Nitride Nanotubes by RF Plasma and Ion Beam

Boron Nitride Nanotubes (BNNT) are one of the candidate materials for storing hydrogen by physical adsorption. It has been reported that this hydrogen storage capacity increases as the crystallinity of the nanostructures decreases. Here, BNNT was synthesized using an RF plasma torch system, and the surface of the BNNT was irradiated with nitrogen ions using an ion beam device, and changes in the surface microstructure were subsequently investigated. A multi-walled BNNT with a wall thickness of about 5 nm was synthesized using a 60 kW RF plasma torch. Amorphous impurities generated during the synthesis process were removed by heat treatment and membrane filtering. Then nitrogen ions were irradiated for 40 minutes at energies of 40 keV and 50 keV, respectively, using an ion beam irradiation device. The changes in the microstructure of the BNNT surface following ion beam irradiation were confirmed by HR-TEM, Raman spectrometer and FT-IR spectrometer. The tube walls of the BNNT were disordered by the nitrogen ions irradiation. At 50 keV, the tube walls located in the middle became disordered, which was attributed to an increase in penetration depth due to the higher irradiation energy. The maximum peak in the Raman spectra and FT-IR spectra of the ion irradiated BNNT were also shifted to a lower frequency. Ion irradiation reduced the crystallinity of the nanostructures. The potential improvement in hydrogen storage capacity by nitrogen ion irradiation of BNNT was confirmed.

Distribution of shallow NV centers in diamond revealed by photoluminescence spectroscopy and nanomachining

We performed nanomachining combined with photoluminescence spectroscopy to understand the depth distribution of nitrogen-vacancy (NV) centers formed by low energy nitrogen ion irradiation of the diamond surface. NV− and NV0 fluorescence signals collected from the surface progressively machined by a diamond tip in an atomic force microscope (AFM) initially rise to a maximum at 5 nm depth before returning to background levels at 10 nm. This maximum corresponds to the defect depth distribution predicted by a SRIM simulation using a 2.5 keV implantation energy per nitrogen atom. Full extinguishing of implantation produced NV− and NV0 zero phonon line peaks occurred beyond 10 nm machining depth, coinciding with the end of easy surface material removal and onset of significant tip wear. The wear ratio of for NV active, ion irradiated diamond compared to the single-crystal diamond tip was surprisingly found to be 22:1. The reported results constitute the first integrated study of in-situ machining and wear characterization via optical properties of the diamond surface containing shallow formed NV centers. We discuss possible metrology applications for diamond tools used in precision manufacturing.

Silicone-based modified layer obtained by low-energy nitrogen ion beam as diaphragm for environmental transmission electron microscope

Amorphous silicon carbonitride (a-SiCN) films were prepared with surface-modified layers of silicone resin and silicone grease, fabricated by low-energy nitrogen ion beam irradiation, for use as diaphragms in an environmental-cell transmission electron microscope (E-TEM). Conditions used during nitrogen ion irradiation for surface modification of silicone polymers were accelerating voltages of 0.8–1.5 kV, ion current densities of 0.70–2.10 μA/cm2, and ion doses of 4.8–8.0 × 1016 ions/cm2. The modified layers, obtained by etching the unmodified layers with hexane, were evaluated by X-ray photoelectron spectroscopy (XPS). The atomic ratio of nitrogen was higher in the modified layer using silicone grease than in the modified layer using silicone resin. The best thinnest and nitriding condition on the silicone grease was obtained through nitrogen ion irradiation using is the case of an accelerating voltage of 0.8 kV, an ion current density of 0.7 μA/cm2, and an ion dose of 4.8 ions/cm2. However, the silicone-grease-based modified layer exhibited much more deflection than the silicone-resin-based modified layer. This is thought to be because the non-modified layer of silicone resin is a tougher material than silicone grease.

Effect of nitrogen ion irradiation treatment to the enhancement of ZnO photocatalytic performance

To overcome the drawbacks of fast charge recombination and the limited visible‐light absorption of semiconductor photocatalysts, N ion irradiation is used to enhance photocatalytic performance of ZnO nanowires. Compared with as‐grown ZnO nanowires, the photocatalytic performance of ZnO under dose of 5 × 1015 cm−2 was efficiently improved because of the bandgap energy decreasing and the introduction of oxygen vacancies defects. On one hand, the reduced bandgap energy improves the easy transfer process of electrons and holes, thus improving the charge separation efficiency, and visible‐light absorption. On the other hand, N ion irradiation increases oxygen vacancy defects and hinders the recombination of photo‐excited electrons and holes. This study has certificated that ion irradiation is an efficient way and created a new insight on the enhancement of photocatalytic activity.

Reprint of "Surface modification of triacetylcellulose by low-energy nitrogen ions for diaphragm of environmental cell transmission electron microscope"

Triacetylcellulose (TAC) was subjected to surface modification by low-energy nitrogen ion irradiation for use as the diaphragm of an environmental cell transmission electron microscope (E-TEM). TAC films formed by the dipping method were placed on Cu grids for E-TEM and then irradiated by nitrogen ions with acceleration voltages of 1.0 and 1.5 kV and with ion doses between 5.9 × 1016 and 1.2 × 1017 ions/cm2. The TAC films were removed by acetone after irradiation and the surface-modified layers at the top were kept for assessment as diaphragms. The thicknesses of the surface-modified layers, which varied depending on the acceleration voltage and dose of the nitrogen ions, ranged from around 12 to 29 nm. X-ray photoelectron spectroscopy revealed that the surface-modified layers mainly consisted amorphous carbon with a nitrogen-to‑carbon atomic ratio of around 1%. These films were transparent to an electron beam accelerated to 300 kV. The pressure resistances of all samples were maintained at around 0.1 MPa.

Dependence on treatment ion energy of nitrogen plasma for oxygen reduction reaction of high ordered pyrolytic graphite

We investigated the contribution of kinetic energy of ions on nitrogen plasma treatment of high ordered pyrolytic graphite (HOPG) film for electro-catalyst material. The treatment was carried out to modify the HOPG surface by nitrogen ion irradiation between 10 and 100 eV using electron-beam-excited plasma (EBEP). In the case of treatment by nitrogen ions with kinetic energy of 60 eV, the oxygen reduction reaction (ORR) activity was markedly improved and the ORR current increased by about 15 times as compared with untreated specimen. The enhancement of ORR activity was explained in terms of an increase of graphitic-N and pyridinic-N components, which act as reaction sites of ORR, from the results of Raman spectroscopy, X-ray photoelectron spectroscopy, low-energy photoelectron counter in air, and atomic force microscopy.

Surface corrugation of carbon fiber via high-fluence nitrogen ion irradiation

SEM and laser goniophotometry were used to study a corrugation of VMN-4 carbon fiber shell of KUP-VM composite after high-fluence 30 keV N2+ ion irradiation at temperatures range from 100 to 600°C. It has been found that the angles of an inclination of corrugated structure increase with temperature so that at temperature ∼270 °C reach maximum values ∼40°, staying at this level at subsequent temperature elevation up to 600 °C. Spatial period of corrugations alternation is about 1 µ m for temperatures range 100-200°C and 0.6 µ m for higher temperatures. Qualitative difference of nitrogen from noble gas temperature dependences of a corrugation is connected with a nitrogen chemical activity and creation of C-N bonds due to implantation.

Nitrogen ion irradiation effect on enhancing photocatalytic performance of CdTe/ZnO heterostructures

To deal with the increasingly deteriorating environment problems, more and more harsh requirements are put forward for photocatalysis application. Building semiconductor heterostructures has been proven to be an efficient way to enhance photocatalytic performance. A kind of CdTe/ZnO heterostructures were synthesized by a hydrothermal and successive ionic layer absorption and reaction (SILAR) method and achieved obviously efficient photocatalytic performance. Moreover, after the N ion irradiation treatment, the photocatalytic activity was further enhanced, which can be ascribed to the introduction of oxygen vacancy defects. The photocatalytic performance enhancement mechanism by coupling constructing heterostructures and ion irradiation are further studied to give us an overall understanding on ZnO nanowires.

Effect of nitrogen ion irradiation parameters on properties of nitrogen-containing carbon coatings prepared by pulsed vacuum arc deposition method

Studies of the effect of nitrogen ion irradiation on the structure and properties of nitrogenated amorphous carbon coatings prepared on polished sitall and silicon substrates by the pulsed vacuum arc deposition method are presented. The techniques used in the investigations were electron energy loss spectroscopy, Raman spectroscopy, and atomic force microscopy. The elemental composition of the coatings was estimated by secondary ion mass spectrometry. It has been found that an increase in the intensity of nitrogen ion irradiation of a carbon nitrogen-containing coating results in an increase in its electrical conductivity, decreases in internal stresses, density, and modulus of elasticity, and also changes in the structure and morphology of the surface. In an additional experiment with a thin a-C:N layer the absence of nitrogen diffusion in a-C during annealing at the temperature up to 1000 °C was confirmed.