In recent years, atomic resolution imaging of two-dimensional (2D) materials using scanning transmission electron microscopy (STEM) has become routine. Individual dopant atoms in 2D materials can be located and identified using their contrast in annular dark-field (ADF) STEM. However, in order to understand the effect of these dopant atoms on the host material, there is now the need to locate and quantify them on a larger scale. In this work, we analyze STEM images of MoS2 monolayers that have been ion-implanted with chromium at ultra-low energies. We use functions from the open-source TEMUL Toolkit to create and refine an atomic model of an experimental image based on the positions and intensities of the atomic columns in the image. We then use the refined model to determine the likely composition of each atomic site. Surface contamination stemming from the sample preparation of 2D materials can prevent accurate quantitative identification of individual atoms. We disregard atomic sites from regions of the image with hydrocarbon surface contamination to demonstrate that images acquired using contaminated samples can give significant atom statistics from their clean regions, and can be used to calculate the retention rate of the implanted ions within the host lattice. We find that some of the implanted chromium ions have been successfully integrated into the MoS2 lattice, with 4.1% of molybdenum atoms in the transition metal sublattice replaced with chromium.

Atom probe tomography was employed to observe and derive the composition of carbon clusters in implanted silicon. This value, which is of interest to the microelectronic industry when considering ion implantation defects, was estimated not to exceed 2 at%. This measurement has been done by fitting the distribution of first nearest neighbor distances between monoatomic carbon ions (C+ and C2+). Carbon quantification has been considerably improved through the detection of molecular ions, using lower electric field conditions as well as equal proportions of 12C and 13C. In these conditions and using another quantification method, we have shown that the carbon content in clusters approaches 50 at%. This result very likely indicates that clusters are nuclei of the SiC phase.

Highly radioactive waste is incorporated into a glass matrix to convert it into a safe, passive form suitable for long-term storage and disposal. It is currently known that alpha decay can generate gaseous species, which can nucleate into bubbles, either through the production of helium or from ballistic collisions with the glass network that liberate oxygen. An effective method to probe this phenomenon utilizes ion beams to either directly implant helium or investigate the damage due to ballistic collisions. This paper provides an overview of the methodology, summarizes the results of current studies, and draws comparisons between them. We find that the irradiation scheme as well as the temperature and composition of the glass are important in determining whether bubble formation will occur. We also explore how analytical techniques can promote bubble formation and suggest avenues for further work.

This article discusses the role of materials science in the growth and processing of silicon that made modern microelectronics possible. The influence of defects on the electronic properties of silicon is explored, followed by the production of electronic-grade silicon and its conversion into macroscopically dislocation-free doped silicon crystals. The intricacies of dopant distributions in as-grown crystals are also discussed. Oxidation, ion implantation, and metallization are essential elements of device processing, and their salient features are emphasized. The electromigration behavior of interconnects and attempts to prevent it are also introduced.

Particle acceleration is an important tool in material modification and several other applications. There are multiple techniques to generate and accelerate ion beams. In the current research work, ions emitted from laser induced plasma were accelerated by employing a DC high voltage extraction assembly. The Nd:YAG laser (1064 nm) with 10 mJ energy and 12 ns pulse width was irradiated on Aluminum target. Thomson parabola technique using Solid State Nuclear Track Detector (CR-39) was employed for measurement of ions energy generated from laser induced plasma. In response to a stepwise increase in acceleration potential from 0–10 kV, an evident increase in energy, in the range 627–730 keV, was observed. In order to utilize this facility as an ion source, Aluminum was exposed to these ions. The Optical and AFM micrographs revealed that the damage produced by the ions on Al surfaces, become more prominent with the increase in ion energy. TRIM simulations were performed for the analysis of the damage at the irradiated samples. Changes in the total displacements, target vacancies and replacement collisions, calculated by TRIM simulation, were analyzed for ion irradiations with increasing ion energies.

The p-type doping of high purity semi-insulating 4H polytype silicon carbide (HPSI 4H-SiC) by aluminum ion (Al+) implantation has been studied in the range of 1 × 1019 to 8 × 1020 /cm3 (0.39 μm implanted thickness) and a conventional thermal annealing of 1950 °C/5 min. Implanted 4H-SiC layers of p-type conductivity and sheet resistance in the range of 1.6 × 104 to 8.9 ×102 Ω□, corresponding to a resistivity in the range of 4.7 × 10−1 to 2.7 × 10−2 Ω cm have been obtained. Hall carrier density and mobility data in the temperature range of 140–720 K feature the transition from a valence band to an intraband conduction for increasing implanted Al ion concentration from 1 × 1019 /cm3 to 4 × 1020 /cm3. A 73% electrical activation, 31% compensation and 146 meV ionization level have been obtained using a best-fit solution of the neutrality equation to Hall carrier data for the lowest concentration.

Unbalanced magnetron sputtering (UBMS) is suitable for the preparation of hard and hydrogen-free diamond-like carbon (DLC) films. Since those films generally suffer from internal stresses and bad adhesion, the addition of a methane source offers two advantages: (i) the control of the film properties by variation of the hydrogen content and (ii) a pretreatment of methane plasma source ion implantation (PSII), which results in a gradient carbon layer within the substrates, ensuring the adhesion of the subsequently deposited DLC films. PSII and UBMS were combined to prepare DLC films on stainless steel substrates and silicon wafers. Different amounts of methane were added to the working gas, argon, to investigate the effect of the hydrogen content on the film properties, i.e., hardness, adhesion, and friction coefficient. Composition and chemical structure of the films were investigated by depth profiling (secondary-ion mass spectrometry) and Raman spectroscopy. Smooth adhesive films could be obtained with the lowest friction coefficient for small additions of methane as a hydrogen source during the sputtering process.

The performance of materials exposed to high doses of neutron radiation is currently of great interest for the development of nuclear fusion energy production. An Fe12%Cr alloy was subjected to high-dose (6 dpa) radiation with 2MeV Fe+ ions to simulate the damage structures caused by neutron radiation, resulting in a damage layer ∼0.7 μm in depth from the surface. Spherical nanoindentation, using indenters with radii of 5, 10, and 20 μm, was used to determine reliable values for the initial yield pressure, the evolution of plastic deformation and the elastic modulus of this material, in the irradiated and unirradiated condition. The results showed that the initial yield pressure within the damage layer can be determined and was approximately a factor of two higher than that of the same material in the unirradiated condition. The irradiated material appeared to display strain softening following yield.

The optical properties of N-ion-implanted diamond are evaluated. The color of implanted layer became glossy black with metallic luster, which was further enhanced after postimplantation annealing at 600 °C for 2 h in vacuum or inert gas atmosphere. Raman spectroscopy revealed that the crystalline diamond became completely disordered after irradiation, but surprisingly the crystalline nature was restored to a mixture of well-defined diamond and diamond-like carbon after annealing. When it was annealed in air at the same temperature, however, the black color disappeared, indicating a removal of the disordered or graphitized layer by oxidation. X-ray photoelectron spectroscopy and Raman analyses indicate that the black color of as-implanted diamond is associated mainly with the disordered carbon and modified band structure. Fourier transform infrared (FTIR) analysis shows that the implanted nitrogen atoms are in N–N and symmetrical 4N-vacancy bonding states, which are commonly found in the natural diamonds with yellow and brown tint.

As deposited amorphous and crystallized thin films of Ti 37.5% Si alloy deposited by pulsed laser ablation technique were irradiated with 100 keV Xe+ ion beam to an ion fluence of about 1016 ions-cm−2. Transmission electron microscopy revealed that the implanted Xe formed amorphous nanosized clusters in both cases. The Xe ion-irradiation favors nucleation of a fcc-Ti(Si) phase in amorphous films. However, in crystalline films, irradiation leads to dissolution of the Ti5Si3 intermetallic phase. In both cases, Xe irradiation leads to the evolution of similar microstructures. Our results point to the pivotal role of nucleation in the evolution of the microstructure under the condition of ion implantation.

Ion implantation has been widely used to improve the mechanical and tribological properties of single crystalline silicon, an essential material for the semiconductor industry. In this study, the effects of four different ion implantations, Ar, C, N, and Ne ions, on the mechanical and tribological properties of single crystal Si were investigated at both the nanoscale and the microscale. Nanoindentation and microindentation were used to measure the mechanical properties and fracture toughness of ion-implanted Si. Nano and micro scratch and wear tests were performed to study the tribological behaviors of different ion-implanted Si. The relationship between the mechanical properties and tribological behavior and the damage mechanism of scratch and wear were also discussed.

Ni was surface-alloyed with Si by ion implantation. The material was examined for its redox and electrocatalytic behavior in NaOH by cyclic voltammetry. The surface was characterized by x-ray photoelectron spectroscopy, x-ray and electron diffraction, and electron and atomic force microscopy. The ion implantation enhanced activity toward the redox conversion of Ni(OH)2 ↔ NiOOH and the anodic oxidation of glucose reached about 3.5 times and about 2.8 times, respectively. The material is an amorphous mixed oxide of Ni and Si. The effect is discussed considering the true surface area and the generation of active surface sites in relation to the oxygen evolution.

The energy spectra of heavy ions emitted from laser-produced plasmas were determined by the use of a technique relying on the implantation of plasma ions into a substrate located close to the plasma. Ion energy spectra were reconstructed from depth profiles of the implanted ions measured by the standard Rutherford back-scattering (RBS) technique employing 2 MeV alpha particles scattered at 170° laboratory angle. The energy spectra of Ag, Au, Sn, and Pb ions, implanted into aluminum or steel foils, are presented. A review of other techniques for ion energy spectrum measurement is presented and their limitations are discussed.

The emergence of miniature light sources such as the vertical-cavity surface-emitting laser (VCSEL) is poised to advance the information age. The development of VCSELs has stimulated a wide range of materials research into epitaxial growth and device-fabrication technologies. In this article, current and emerging applications that are guiding the commercial development of VCSELs are first considered, followed by discussions of the VCSEL epitaxial structure and fabrication technologies. This brief overview will also mention recent efforts aimed at achieving long-wavelength VCSELs grown on GaAs substrates, as well as approaches for achieving a high modulation rate.

A systematic investigation of damage accumulation in GaN films induced by Ar+ as a function of implantation temperature and dose rate has been conducted. Depth distribution of disorder was measured by Rutherford Backscattering/Channeling spectrometry. Two disordered regions were identified in the damage depth distribution: a surface peak and a bulk damage peak. These regions exhibited different behavior as a function of implantation temperature. The displaced atomic density in the bulk damage peak displayed a “reverse annealing” behavior in temperature range from 500 °C to 700 °C, which we attributed to formation of characteristic secondary defects. The influence of implantation temperature and dose rate on the radiation damage accumulation is discussed.

Nanocrystalline diamond films deposited by microwave plasma chemical vapor deposition (MWPCVD) method were observed on Si substrates implanted with phosphor (P) and boron (B) ions at room temperature via scanning electron microscopy (SEM). The relations between the species, energies and doses of implanted impurities and the nucleation, grain size and morphology of diamond were studied. The results present that different nucleation density from 106 cm-2 to 109 cm-2 can be obtained on implanted and unscratched Si, which is larger of 3–6 magnitude orders than that on mirror-polished Si. The nano-structured diamond films can be deposited on scratched Si substrates implanted by higher concentration of phosphor and boron ions. The grain sizes of nano-structured films can be adjusted by controlling the implanted energies and doses, and nano-structured films can be synthesized with low impressive stress. The Raman spectroscopy was employed to analysis the phase purity of nano-structured film, which shows a broad peak at around 1150 cm-1 relative to the nano-structured and tetrahedrally bonded carbon network.

Strained layer heterostructures provide ideal systems with which to study the dynamics of dislocation motion via in situ transmission electron microscopy, as the geometry, strain state, and kinetics can be characterized and directly controlled. We discuss how these structures are used to study dislocation-point defect interactions, emphasizing the experimental requirements necessary for quantification of dislocation motion. Following ion implantation, different concentrations and types of point defects are introduced within the SiGe epilayer depending on the implantation species, energy, and current density. By annealing samples in situ in the transmission electron microscope (TEM) following implantation, we can directly observe dislocation motion and quantify the effect of dislocation-point defect interactions on dislocation velocities. We find that dislocation motion is impeded if the implantation dose peak lies within the epilayer, as dislocations pin at point defect atmospheres. Shallow BF2 implantation into the sample capping layer results in more complicated behavior. For low current density implants, dislocation velocities may be dramatically increased; at higher current densities the magnitude of this increase is significantly smaller. Implantation of different ions separately implicates fluorine as the species responsible for the observed increases in dislocation velocities, presumably due to an electrical effect on the rate of dislocation kink nucleation.