Ion Implantation Research Articles

Nickel nitride-mediated nitric oxide generation for combating implant-associated infections

NiTi alloys are widely used in the fabrication of biomedical implants, and it is essential to endow them with selective antibacterial properties to avoid implant-associated infection. In this study, nickel nitride (Ni3N), as a promising new inorganic nitric oxide (NO) donor, was in situ constructed on the surface of NiTi alloys through a straightforward two-step plasma immersion ion implantation (PIII) strategy. Nickel sites were first exposed by physical bombardment with argon or metal plasma, followed by reaction with nitrogen plasma to form Ni3N. Ni3N can disrupt the transmembrane proton electrochemical gradient by capturing protons to produce ammonia species (NHx), resulting in the accumulation of reactive oxygen species (ROS) as a result of bacterial metabolic disruption. On the other hand, the generated NHx can further react with ROS to produce NO and reactive nitrogen species (RNS). As a result, the Ni3N films exhibited more than 99 % antibacterial efficiency against both gram-negative and gram-positive bacteria. They also demonstrated effective antibacterial properties in a rat subcutaneous implant model. In addition, the modified NiTi alloys exhibit good corrosion resistance and cytocompatibility. This study provides a green, safe, and inexpensive method for constructing metal nitride films on implant surfaces and offers new ideas for the clinical design and fabrication of novel antibacterial implants.

Impact of Sequential N Ion Implantation on Extended Defects and Mg Distribution in Mg Ion‐Implanted GaN

In Mg ion implantation doping of GaN, sequential N ion implantation reportedly changes Mg concentrations in the Mg ion‐implanted region and the underlying region after activation annealing. The impact of sequential N ion implantation on defects and Mg distribution after postimplantation annealing is investigated. The atomic‐resolution analyses show that, in the Mg ion‐implanted region, the N ion implantation increases the concentration of MgGa. It is thus concluded that the Mg soluble in GaN by Mg ion implantation is increased by N ion implantation. The rest of the Mg atoms agglomerate to form clusters on the extended defects, and their concentration is also increased by the N implantation. The coarsening of extended defects is suppressed by the N ion implantation: the defects in the Mg+N‐implanted sample are nanoscale interstitial‐type defects, and they do not grow or annihilate after annealing. This indicates that the N implantation changes the concentrations of interstitials.

Nanoscale doping of polymeric semiconductors with confined electrochemical ion implantation.

Nanoresolved doping of polymeric semiconductors can overcome scaling limitations to create highly integrated flexible electronics, but remains a fundamental challenge due to isotropic diffusion of the dopants. Here we report a general methodology for achieving nanoscale ion-implantation-like electrochemical doping of polymeric semiconductors. This approach involves confining counterion electromigration within a glassy electrolyte composed of room-temperature ionic liquids and high-glass-transition-temperature insulating polymers. By precisely adjusting the electrolyte glass transition temperature (Tg) and the operating temperature (T), we create a highly localized electric field distribution and achieve anisotropic ion migration that is nearly vertical to the nanotip electrodes. The confined doping produces an excellent resolution of 56 nm with a lateral-extended doping length down to as little as 9.3 nm. We reveal a universal exponential dependence of the doping resolution on the temperature difference (Tg - T) that can be used to depict the doping resolution for almost infinite polymeric semiconductors. Moreover, we demonstrate its implications in a range of polymer electronic devices, including a 200% performance-enhanced organic transistor and a lateral p-n diode with seamless junction widths of <100 nm. Combined with a further demonstration in the scalability of the nanoscale doping, this concept may open up new opportunities for polymer-based nanoelectronics.

Analytical model of modified diamond tools temperature by focused ion beam in dry diamond turning

The contact process between the chip and the rake face is directly affected by the temperature of the rake face, and then tool wear and machining quality is indirectly influenced by it. In this study, a temperature prediction model for the rake face of modified diamond tools during dry turning of the 6061 aluminum alloy was established based on the moving heat source method. The shear heat source, rake face chip friction heat source, cutting edge-workpiece ploughing effect heat source, cutting edge workpiece roll burnishing heat source, and flank face workpiece elastic recovery heat source were considered by this model during the dry diamond turning, simultaneously considering the non-uniformity of heat source intensity and heat distribution ratio, as well as the influence of ion implantation on the temperature of the tool rake face. The experimental results indicate that this model successfully predicts the temperature of the modified tool rake face, and it is found that an increase in dose will promote a decrease in the temperature of the rake face. Theoretical analysis reveals that modified cutting tools have the characteristic of reducing the temperature of the rake face, revealing the essence of the influence of “modification” on the temperature of the rake face from the perspective of the cutting mechanism, and providing a theoretical basis for optimizing modification parameters.

Modification of the Properties of Titanium Carbide MXene by Ag Doping via Ion Implantation for Quantum Dot-Sensitized Solar Cell Applications

Modification of the Properties of Titanium Carbide MXene by Ag Doping via Ion Implantation for Quantum Dot-Sensitized Solar Cell Applications

Surface modification of nickel-phosphorus plating by Ti ion implantation for chalcogenide glass lens molding

Nickel-phosphorus (Ni-P) plating has been developed as an excellent mold material in precision glass molding (PGM) for silicate optical lenses. However, the elemental diffusion and adhesion problems hinder the application of the Ni-P mold in the molding process for infrared chalcogenide glass (ChG) optics. In this study, Ti ion implantation and annealing were proposed for the surface modification of Ni-P plating. The modification mechanism of the Ti-Ni-P plating was studied, and the Ti ion distribution was simulated using the Monte Carlo method. Several characterization methods were conducted to analyze the surface composition of Ti-Ni-P plating. The mechanical properties of the plating were tested before and after implantation, proving that ion implantation improved the surface hardness of the plating. Finally, molding experiments were carried out using the Ti implanted flat and structured molds. The molded glass does not undergo interfacial reaction, and has high structural replication accuracy and higher infrared transmittance. It is validated that Ti ion implantation has a positive effect on the inhibition of the interfacial reaction in ChG molding.

Plotting philosophy picture of uniaxial magnetic anisotropy in arsenide and phosphide dilute ferromagnetic semiconductors

In this work, we performed a systematic investigation on the comparison of magnetic anisotropy between three III-Mn-V dilute ferromagnetic semiconductors (Ga,Mn)As, (In,Mn)As and (Ga,Mn)P prepared by ion implantation and pulsed laser melting. Compressive strain induces in-plane magnetic anisotropy in (Ga,Mn)As and (Ga,Mn)P, while out-of-plane magnetic anisotropy is present in (In,Mn)As due to tensile strain introduced by Mn substitution. Interestingly, all materials prepared herein does not present strong in-plane uniaxial anisotropy, between [110] and [11¯0] directions, which always exhibits in low temperature molecular beam epitaxy (LT-MBE) grown (Ga,Mn)As samples. The reason is ascribed to the fact that the ultra-fast recrystallization induced by pulsed laser melting weakens the formation of Mn-Mn dimers along the [11¯0] direction which presents in LT-MBE grown (Ga,Mn)As.

The synergistic effect of body modification and surface coating for the moisture barrier of hydrophilic PU film

Polyurethane (PU) films have established a distinctive position among various protective materials due to their outstanding chemical and physical properties. However, their limited moisture barrier performance hinders their broader applications. To solve this difficult problem, PU film is first modified by adding reactive fillers (MgO) and physical barrier fillers (Modified graphene oxide, M-GO), and then Si-DLC coating is deposited on the surface of the film by hollow cathode plasma immersion ion implantation (HCPIII) method at near room temperature. MgO can react with the water molecules diffused into the film, while the addition of M-GO extends the diffusion path of water molecules. It is revealed that the addition of 5% MgO and 0.5% M-GO, along with the deposition of a 2.56 μm Si-doped DLC coating, leads to a remarkable 14.67-fold reduction in the water vapor transmittance rate (WVTR). The result of molecular dynamics simulations shows that the reactive sheet filler captures the water molecules and reduces the WVTR. In addition, the combination method of PU body modification and surface coating is suitable for polyurethane foam (PUF) to reduce the WVTR as a double coating. It's amazing that the WVTR of PUF significantly reduces by 15.29 times after double-coating. The combination of body modification and surface coating provides an effective route for significantly improving the moisture barrier property of hydrophilic polymer film and polymer foam.

Direct Synthesis of Layer‐Tunable and Transfer‐Free Graphene on Device‐Compatible Substrates Using Ion Implantation Toward Versatile Applications

Direct synthesis of layer‐tunable and transfer‐free graphene on technologically important substrates is highly valued for various electronics and device applications. State of the art in the field is currently a two‐step process: a high‐quality graphene layer synthesis on metal substrate through chemical vapor deposition (CVD) followed by delicate layer transfer onto device‐relevant substrates. Here, we report a novel synthesis approach combining ion implantation for a precise graphene layer control and dual‐metal smart Janus substrate for a diffusion‐limiting graphene formation to directly synthesize large area, high quality, and layer‐tunable graphene films on arbitrary substrates without the post‐synthesis layer transfer process. Carbon (C) ion implantation was performed on Cu–Ni film deposited on a variety of device‐relevant substrates. A well‐controlled number of layers of graphene, primarily monolayer and bilayer, is precisely controlled by the equivalent fluence of the implanted C‐atoms (1 monolayer ~4 × 1015 C‐atoms/cm2). Upon thermal annealing to promote Cu‐Ni alloying, the pre‐implanted C‐atoms in the Ni layer are pushed toward the Ni/substrate interface by the top Cu layer due to the poor C‐solubility in Cu. As a result, the expelled C‐atoms precipitate into a graphene structure at the interface facilitated by the Cu‐like alloy catalysis. After removing the alloyed Cu‐like surface layer, the layer‐tunable graphene on the desired substrate is directly realized. The layer‐selectivity, high quality, and uniformity of the graphene films are not only confirmed with detailed characterizations using a suite of surface analysis techniques but more importantly are successfully demonstrated by the excellent properties and performance of several devices directly fabricated from these graphene films. Molecular dynamics (MD) simulations using the reactive force field (ReaxFF) were performed to elucidate the graphene formation mechanisms in this novel synthesis approach. With the wide use of ion implantation technology in the microelectronics industry, this novel graphene synthesis approach with precise layer‐tunability and transfer‐free processing has the promise to advance efficient graphene‐device manufacturing and expedite their versatile applications in many fields.

Ion implantation induced p-type conductivity in FeS2 thin film

In pursuing sustainable energy solutions, thin-film solar cells based on the Copper zinc tin sulfide (CZTS) absorber material have garnered significant attention due to their earth-abundant and non-toxic composition. However, the modest efficiency demonstrated by CZTS solar cells has prompted researchers to investigate novel approaches to improve their performance. An area of potential advancement entails the integration of appropriate hole transport layers (HTLs). In this simulation-based study, we focused on FeS2 as a highly promising candidate for use as an HTL in CZTS-based solar cells. FeS2, traditionally considered n-type, was tailored to achieve p-type conductivity through the negative ion implantation (O, P, and As) process. 40 keV ion beam was utilized, with three doses (105, 1010, 1015 cm−2) applied for each ion beam. We demonstrate successful p-type doping of FeS2 with a hole concentration of ∼1020 cm−3 in case of 1015 cm−2 dose, paving the way for its integration as an effective HTL within the CZTS solar cell structure.

Nanopatterning Induced Si Doping in Amorphous Ga2O3 for Enhanced Electrical Properties and Ultra-Fast Photodetection.

Ga2O3 has emerged as a promising material for the wide-bandgap industry aiming at devices beyond the limits of conventional silicon. Amorphous Ga2O3 is widely being used for flexible electronics, but suffers from very high resistivity. Conventional methods of doping like ion implantation require high temperatures post-processing, thereby limiting their use. Herein, an unconventional method of doping Ga2O3 films with Si, thereby enhancing its electrical properties, is reported. Ion-beam sputtering (500eV Ar+) is utilized to nanopattern SiO2-coated Si substrate leaving the topmost part rich in elemental Si. This helps in enhancing the carrier conduction by increasing n-type doping of the subsequently coated 5nm amorphous Ga2O3 films, corroborated by room-temperature resistivity measurement and valence band spectra, respectively, while the nanopatterns formed help in better light management. Finally, as proof of concept, metal-semiconductor-metal (MSM) photoconductor devices fabricated on doped, rippled films show superior properties with responsivity increasing from 6 to 433mAW-1 while having fast detection speeds of 861µs/710µs (rise/fall time) as opposed to non-rippled devices (377ms/392ms). The results demonstrate a facile, cost-effective, and large-area method to dope amorphous Ga2O3 films in a bottom-up approach which may be employed for increasing the electrical conductivity of other amorphous oxide semiconductors as well.

Tailoring the electrical and magneto-electric transport properties of ZnO films via Ti ion implantation

A significant development toward semiconductor-based electronic devices is based on the electric and magneto-electric control of the transport properties of the charge carriers. This study unprecedentedly investigates the Ti implantation and thereafter the effect of structural defects on the electrical and magneto-electric transport properties of Ti-implanted RF-sputtered ZnO thin films. Theoretical stopping and range of ions in matter simulations along with the experimental structural and elemental studies reveal that Ti ion implantation generates a significant amount of oxygen vacancy (VO) defects apart from Ti-related impurities in post-implantation annealed films. The film implanted with 8 × 1015 ions/cm2 (TZO815) exhibits the lowest resistivity (4.68 × 10−3 Ω cm) and the highest carrier concentration (6.61 × 1020 cm−3) values. Resistivity measurements over a temperature range of 5-300K indicate semiconducting behavior for all the films implanted up to fluences of 5 × 1015 ions/cm2 identified with a grain boundary dominated thermally activated band, nearest neighbor hopping, and Mott and Efros–Shklovskii (ES) variable range hopping conduction mechanisms at various temperature intervals. Notably, the gradual decrease in both Mott and ES hopping ranges following Ti implantation indicates the formation of more localized states. Interestingly, the TZO815 film exhibits metal-semiconductor transition around 220 K, suggesting the formation of a degenerate band within the ZnO conduction band upon Ti implantation. Remarkably, the magnetoresistance results align with a semiempirical formula proposed by Khosla and Fischer, indicating that a negative magneto resistance in the TZO thin films is attributed to the spin-dependent scattering of conduction electrons by the localized magnetic moments induced mainly by the implantation induced VO defects.

High-efficiency and high-brightness broad area laser diodes with buried implantation current blocking

Buried-regrown-implant-structure (BRIS) technology combines two-step epitaxial regrowth with an intermediate ion implantation step in order to realise a buried current aperture close to the active region of a laser diode. In this paper we carry out a systematic performance comparison demonstrating the benefit of BRIS technology in single emitter broad-area lasers (BALs). We investigate stripe width W = 100 μ m and resonator length L = 4 mm single emitter lasers emitting at wavelength λ = 915 nm, comparing the performance of BRIS devices with different implantation depths with reference devices with only contact layer implantation. We show that using BRIS technology we achieve a continuous wave output power of 20 W at 57% efficiency, with a peak efficiency of 68%, and maintain a lateral brightness of 3.4 mm · mrad up to 19 W, improved over the reference devices due to reduced lateral current spreading in the BRIS devices. Further, we show results of ongoing aging experiments, which has shown no device degradation up to 5000 hours from BRIS devices.

Effects of ion implantation with arsenic and boron in germanium-tin layers

Ion implantation is widely used in the complementary metal–oxide–semiconductor process, which stimulates to study its role for doping control in rapidly emerging group IV Ge1−xSnx materials. We tested the impact of As and B implantation and of subsequent rapid thermal annealing (RTA) on the damage formation and healing of the Ge1−xSnx lattice. Ion implantation was done at 30, 40, and 150 keV and with various doses. The implantation profiles were confirmed using secondary ion mass spectrometry. X-ray diffraction in combination with Raman and photoluminescence spectroscopies indicated notable crystal damage with the increase of the implantation dose and energy. Significant damage recovery was confirmed after RTA treatment at 300 °C and to a larger extent at 400 °C for a Ge1−xSnx sample with Sn content less than 11%. A GeSn NP diode was fabricated after ion implantation. The device showed rectifying current-voltage characteristics with maximum responsivity and detectivity of 1.29 × 10−3 A/W and 3.0 × 106 cm (Hz)1/2/W at 77 K, respectively.

Position‐Selective Introduction of Ferromagnetism on the Micro‐ and Nanoscale in a Paramagnetic Thin Palladium Film

Postsynthetic, position‐selective addition of properties to materials constitutes a paradigm shifting step in materials engineering. The approach enables creation of material systems inaccessible by equilibrium and near‐equilibrium synthesis and can be applied in novel practical applications as well as fundamental physics studies over a range of length and energy scales. Ion implantation is a versatile, scalable, industry‐compatible tool, enabling the next step in this development. Herein, ion implantation is used to design and functionalize a mesoscopic magnetic architecture. A self‐supporting mask is combined with implantation of 60 keV Fe ions to create an embedded array of ≈8 μm‐wide circular ferromagnetic regions in a Pd film. The approach is contactless, free from surface residues, and requires no focusing or scanning of the beam. Magnetic properties of the array are probed with longitudinal magneto‐optic Kerr effect measurement while varying sample temperature and applied magnetic field. Microstructures are visualized with Kerr microscopy and compared to the Fe distribution measured with microbeam proton‐induced X‐Ray emission. Sample topography after implantation is obtained by atomic force microscopy, while ion beam analysis is used to probe concentration depth profiles of implanted Fe, impurities, and to investigate material mixing.

Improving hydrogen isotope permeation resistance of (TiVAlCrZr)O multi-component metal oxide coating by O+ Ion implantation

Oxygen vacancy can greatly affect the performance of metal oxide to hydrogen isotope permeation resistance. In this work, we report a new strategy to improve the permeation resistance by oxygen ion implantation. A (TiVAlCrZr)O multi-component metal oxide film was prepared as a tritium permeation barrier on a 316 L substrate by RF magnetron sputtering deposition, and then implanted by oxygen ions to fill the oxygen vacancies inside. The grazing incidence X-rays (GIXRD) analysis showed that the pristine and the oxygen-implanted coatings were in an amorphous phase. The deuterium permeation resistance of the four coatings was tested by a gas-driven device. The result showed that the pristine coating had a permeation reduction factor (PRF) of 5,610 at 500 °C, while there was a 13.6 times of increase in PRF with an oxygen concentration of 11.4 at.% with the best-reported value of 76,500, and more oxygen ions implanted, the better the deuterium permeation resistance of the coating. The GIXRD showed that after the test the pristine coating remained amorphous, while some crystals were formed in the oxygen-implanted coating with an oxygen concentration of 11.4 at.%. Oxygen ion implantation enhanced the deuterium permeation resistance by filling the oxygen vacancies and forming of more stable state of amorphous multi-component metal oxide, which is expected to be a new type of deuterium permeation barrier.

Protecting Orthopaedic Implants from Infection: Antimicrobial Peptide Mel4 Is Non-Toxic to Bone Cells and Reduces Bacterial Colonisation When Bound to Plasma Ion-Implanted 3D-Printed PAEK Polymers.

Even with the best infection control protocols in place, the risk of a hospital-acquired infection of the surface of an implanted device remains significant. A bacterial biofilm can form and has the potential to escape the host immune system and develop resistance to conventional antibiotics, ultimately causing the implant to fail, seriously impacting patient well-being. Here, we demonstrate a 4 log reduction in the infection rate by the common pathogen S. aureus of 3D-printed polyaryl ether ketone (PAEK) polymeric surfaces by covalently binding the antimicrobial peptide Mel4 to the surface using plasma immersion ion implantation (PIII) treatment. The surfaces with added texture created by 3D-printed processes such as fused deposition-modelled polyether ether ketone (PEEK) and selective laser-sintered polyether ketone (PEK) can be equally well protected as conventionally manufactured materials. Unbound Mel4 in solution at relevant concentrations is non-cytotoxic to osteoblastic cell line Saos-2. Mel4 in combination with PIII aids Saos-2 cells to attach to the surface, increasing the adhesion by 88% compared to untreated materials without Mel4. A reduction in mineralisation on the Mel4-containing surfaces relative to surfaces without peptide was found, attributed to the acellular portion of mineral deposition.

Coatless modification of 3D-printed Ti6Al4V implants through tailored Cu ion implantation combined with UV photofunctionalization to enhance cell attachment, osteogenesis and angiogenesis

The three-dimensional-printed Ti6Al4V implant (3DTi) has been widely accepted for the reconstruction of massive bone defects in orthopedics owing to several advantages, such as its tailored shape design, avoiding bone graft and superior bone-implant interlock. However, the osteoinduction activity of 3DTi is inadequate when applied clinically even though it exhibits osteoconduction. This study developes a comprehensive coatless strategy for the surface improvement of 3DTi through copper (Cu) ion implantation and ultraviolet (UV) photofunctionalization to enhance osteoinductivity. The newly constructed functional 3DTi (UV/Ti-Cu) achieved stable and controllable Cu doping, sustained Cu2+ releasing, and increased surface hydrophilicity. By performing cellular experiments, we determined that the safe dose range of Cu ion implantation was less than 5×1016 ions/cm2. The implanted Cu2+ enhanced the ALP activity and the apatite formation ability of bone marrow stromal cells (BMSCs) while slightly decreasing proliferation ability. When combined with UV photofunctionalization, cell adhesion and proliferation were significantly promoted and bone mineralization was further increased. Meanwhile, UV/Ti-Cu was conducive to the migration and angiogenesis of human umbilical vein endothelial cells (HUVECs) in vitro, theoretically facilitating vascular coupling osteogenesis. In conclusion, UV/Ti-Cu is a novel attempt to apply two coatless techniques for the surface modification of 3DTi. In addition, it is considered a potential bone substrate for repairing bone defects.

Activation of telecom emitters in silicon upon ion implantation and ns pulsed laser annealing

Recent demonstrations of optically active telecom emitters show that silicon is a compelling candidate for solid-state quantum photonic platforms. In particular, the fabrication of a defect known as the G center has been shown in carbon-rich silicon upon conventional thermal annealing. However, the high-yield controlled fabrication of these emitters at the wafer scale still requires the identification of a suitable thermodynamic pathway enabling its activation following ion implantation. Here we demonstrate the activation of G centers in high-purity silicon substrates upon nanosecond pulsed laser annealing. The proposed method enables non-invasive, localized activation of G centers by the supply of short non-stationary pulses, thus overcoming the limitations of conventional rapid thermal annealing related to the structural metastability of the emitters. A finite-element analysis highlights the strong non-stationarity of the technique, offering radically different defect-engineering capabilities with respect to conventional longer thermal treatments, paving the way to the direct and controlled fabrication of emitters embedded in integrated photonic circuits and waveguides.

Restoring the electronic properties of epitaxial graphene on SiC substrate by Ar intercalation

Thermal decomposition of 6H–SiC(0001) under an argon atmosphere is a promising technique to fabricate large-scale epitaxial graphene monolayers for electronic applications. In this manuscript, we report on the intercalation of argon, hydrogen and oxygen atoms underneath a graphene buffer layer (BL) on SiC(0001), involving bond formation between the intercalated agent and Si atoms. Density Functional Theory calculations were performed to investigate the atomic structure, stability and electronic properties of quasi free-standing monolayer graphene and bilayer graphene, accomplished by intercalation. According to our results, as the Ar intercalated atoms saturate the silicon dangling bonds in the upper SiC surface, the BL is completely detached from the substrate and transformed into free-standing graphene. Ar intercalation would be hindered by the concurrent and thermodynamically more spontaneous adsorption of Ar atop the graphene layers, resulting in a pronounced decrease of the process efficiency. High Ar-coverage regimes and low kinetic barriers for Ar intercalation might shift the intercalation/adsorption balance. These factors as well as strategies such as ion implantation could be explored to identify more favorable conditions to experimentally test Ar intercalation as a simple method to achieve control of the electronic properties of the BL and help preserve the unique characteristics of graphene.