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For many years, Si1−yGey alloys have been applied in the semiconductor industry due to the ability to adjust the performance of Si-based nanoelectronic devices. Following this alloying approach of group-IV semiconductors, adding tin (Sn) into the alloy appears as the obvious next step, which leads to additional possibilities for tailoring the material properties. Adding Sn enables effective bandgap and strain engineering and can improve the carrier mobilities, which makes Si1−x−yGeySnx alloys promising candidates for future opto- and nanoelectronics applications. The bottom-up approach for epitaxial growth of Si1−x−yGeySnx, e.g., by chemical vapor deposition and molecular beam epitaxy, allows tuning the material properties in the growth direction only; the realization of local material modifications to generate lateral heterostructures with such a bottom-up approach is extremely elaborate, since it would require the use of lithography, etching, and either selective epitaxy or epitaxy and chemical–mechanical polishing, giving rise to interface issues, non-planar substrates, etc. This article shows the possibility of fabricating Si1−x−yGeySnx alloys by Sn ion beam implantation into Si1−yGey layers followed by millisecond-range flash lamp annealing (FLA). The materials are investigated by Rutherford backscattering spectrometry, micro-Raman spectroscopy, x-ray diffraction, and transmission electron microscopy. The fabrication approach was adapted to ultra-thin Si1−yGey layers on silicon-on-insulator substrates. The results show the fabrication of single-crystalline Si1−x−yGeySnx with up to 2.3 at. % incorporated Sn without any indication of Sn segregation after recrystallization via FLA. Finally, we exhibit the possibility of implanting Sn locally in ultra-thin Si1−yGey films by masking unstructured regions on the chip, thus demonstrating the realization of vertical as well as lateral Si1−x−yGeySnx heterostructures by Sn ion implantation and flash lamp annealing. [ABSTRACT FROM AUTHOR]

RE-doped β-Ga2O3 seems attractive for future high-power LEDs operating in high irradiation environments. In this work, we pay special attention to the issue of radiation-induced defect anisotropy in β-Ga2O3, which is crucial for device manufacturing. Using the RBS/c technique, we have carefully studied the structural changes caused by implantation and post-implantation annealing in two of the most commonly used crystallographic orientations of β-Ga2O3, namely the (-201) and (010). The analysis was supported by advanced computer simulations using the McChasy code. Our studies reveal a strong dependence of the structural damage induced by Yb-ion implantation on the crystal orientation, with a significantly higher level of extended defects observed in the (-201) direction than for the (010). In contrast, the concentration and behavior of simple defects seem similar for both oriented crystals, although their evolution suggests the co-existence of two different types of defects in the implanted zone with their different sensitivity to both, radiation and annealing. It has also been found that Yb ions mostly occupy the interstitial positions in β-Ga2O3 crystals that remain unchanged after annealing. The location is independent of the crystal orientations. We believe that these studies noticeably extend the knowledge of the radiation-induced defect structure, because they dispel doubts about the differences in the damage level depending on crystal orientation, and are important for further practical applications. [ABSTRACT FROM AUTHOR]

RE-doped β-Ga2O3 seems attractive for future high-power LEDs operating in high irradiation environments. In this work, we pay special attention to the issue of radiation-induced defect anisotropy in β-Ga2O3, which is crucial for device manufacturing. Using the RBS/c technique, we have carefully studied the structural changes caused by implantation and post-implantation annealing in two of the most commonly used crystallographic orientations of β-Ga2O3, namely the (-201) and (010). The analysis was supported by advanced computer simulations using the McChasy code. Our studies reveal a strong dependence of the structural damage induced by Yb-ion implantation on the crystal orientation, with a significantly higher level of extended defects observed in the (-201) direction than for the (010). In contrast, the concentration and behavior of simple defects seem similar for both oriented crystals, although their evolution suggests the co-existence of two different types of defects in the implanted zone with their different sensitivity to both, radiation and annealing. It has also been found that Yb ions mostly occupy the interstitial positions in β-Ga2O3 crystals that remain unchanged after annealing. The location is independent of the crystal orientations. We believe that these studies noticeably extend the knowledge of the radiation-induced defect structure, because they dispel doubts about the differences in the damage level depending on crystal orientation, and are important for further practical applications. [ABSTRACT FROM AUTHOR]

Abstract RE-doped β-Ga2O3 seems attractive for future high-power LEDs operating in high irradiation environments. In this work, we pay special attention to the issue of radiation-induced defect anisotropy in β-Ga2O3, which is crucial for device manufacturing. Using the RBS/c technique, we have carefully studied the structural changes caused by implantation and post-implantation annealing in two of the most commonly used crystallographic orientations of β-Ga2O3, namely the (-201) and (010). The analysis was supported by advanced computer simulations using the McChasy code. Our studies reveal a strong dependence of the structural damage induced by Yb-ion implantation on the crystal orientation, with a significantly higher level of extended defects observed in the (-201) direction than for the (010). In contrast, the concentration and behavior of simple defects seem similar for both oriented crystals, although their evolution suggests the co-existence of two different types of defects in the implanted zone with their different sensitivity to both, radiation and annealing. It has also been found that Yb ions mostly occupy the interstitial positions in β-Ga2O3 crystals that remain unchanged after annealing. The location is independent of the crystal orientations. We believe that these studies noticeably extend the knowledge of the radiation-induced defect structure, because they dispel doubts about the differences in the damage level depending on crystal orientation, and are important for further practical applications.

β-Ga2O3 is an ultra-wide bandgap semiconductor (Eg~4.8 eV) of interest for many applications, including optoelectronics. Undoped Ga2O3 emits light in the UV range that can be tuned to the visible region of the spectrum by rare earth dopants. In this work, we investigate the crystal lattice recovery of (2 ¯ 01) -oriented β-Ga2O3 crystals implanted with Yb ions to the fluence of 1 ×1014 at/cm2. Post-implantation annealing at a range of temperature and different atmospheres was used to investigate the β-Ga2O3 crystal structure recovery and optical activation of Yb ions. Ion implantation is a renowned technique used for material doping, but in spite of its many advantages such as the controlled introduction of dopants in concentrations exceeding the solubility limits, it also causes damage to the crystal lattice, which strongly influences the optical response from the material. In this work, post-implantation defects in β-Ga2O3:Yb crystals, their transformation, and the recovery of the crystal lattice after thermal treatment have been investigated by channeling Rutherford backscattering spectrometry (RBS/c) supported by McChasy simulations, and the optical response was tested. It has been shown that post-implantation annealing at temperatures of 700–900 °C results in partial crystal lattice recovery, but it is accompanied by the out-diffusion of Yb ions toward the surface if the annealing temperature and time exceed 800 °C and 10 min, respectively. High-temperature implantation at 500–900 °C strongly limits post-implantation damage to the crystal lattice, but it does not cause the intense luminescence of Yb ions. This suggests that the recovery of the crystal lattice is not a sufficient condition for strong rare-earth photoluminescence at room temperature and that oxygen annealing is beneficial for intense infrared luminescence compared to other tested environments. [ABSTRACT FROM AUTHOR]

Atomic layer deposited (ALD) TiO2 layers are implanted with N, O, and Ar ions to reduce the bandgap, thereby increasing its absorbance in the visible region. The implantation is accomplished with 40 keV nitrogen, 45 keV oxygen, and 110 keV argon ions in the fluence range 1 × 1015 to 5.6 × 1016 ions cm−2. The energy of each incident ion is tuned using stopping and range of ions in matter (SRIM) to produce defects around the same projected range. The structural analysis of the as‐deposited film is performed through X‐ray diffraction (XRD), scanning electron microscopy (SEM), Rutherford backscattering (RBS), and time of flight elastic recoil detection analysis (ToF‐ERDA). The implanted layers are characterized using diffuse reflectance spectroscopy (DRS) and Fourier transform infrared spectroscopy (FTIR) to study the optical and vibrational properties of the films. The results demonstrate that nitrogen implantation in TiO2 reduces the reflectance from 43.52% to 26.31% and bandgap from 2.68 to 2.61 eV, making it a promising bandgap‐engineered material for capping layers in solar cell applications. The refractive index of the 40 keV nitrogen ion implanted film at 1 × 1016 ions cm−2 (N‐16) increases from ≈2.8 to ≈2.95. OPAL2 solar cell simulations show that the N‐16 implanted TiO2 anti‐reflective coatings (ARC) can enhance the absorbed photocurrent by 7.3%. [ABSTRACT FROM AUTHOR]

TiO2 thin films are synthesized by using DC magnetron sputtering system on Si (100) substrates and then annealed in a muffled furnace at 450 °C. Annealed samples are irradiated with carbon ions accelerated at the energy of 300 keV at various carbon ion doses of 4.2 × 1012, 6.3 × 1013, 1.2 × 1014 and 2.5 × 1014 ions/cm2. Structural and optical properties are studied by using different techniques such as x-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, photo-luminescence spectroscopy and diffuse reflectance spectroscopy (DRS). The results show that structural and optical properties of the thin films modify with the amount of carbon ion doses. The synthesized thin film without ions irradiation has the rutile phase preferably, and by increasing the ion dose, it is changing into the anatase phase. Smaller crystallite size results in to the agglomeration process, and however, crystal size decreases with ion dose. PL spectra also confirm the formation of anatase phase from the rutile phase and different energy states due to the carbon ion implantation within the TiO2 phase. The creation of energy states are linked with defects induced into the thin films and are required to improve the photocatalytic properties due to the hopping mechanism. DRS results show that bandgap of the pure TiO2 thin film is 2.4 eV and it decreases to 2.1 eV by increasing the carbon ions dose. The achievement of this small band gap is attributed to the decrease in crystallite sizes and the defects induced by the ion implantation. [ABSTRACT FROM AUTHOR]

This research addresses an analytical methodology to quantify elements of interest in fusion‐relevant materials using secondary ion mass spectrometry (SIMS). For this purpose, internal standards have been fabricated by ion implantation to avoid the well‐known matrix effect of this technique. In particular, chromium has been implanted at an energy of 12 MeV using two fluences in high‐purity iron and tungsten matrices together with Si control substrates. The latter were applied to determine the Cr concentration implanted through experimental and semiempirical methods. Specifically, the IBA technique Rutherford backscattering spectrometry (RBS) provided the quantitative results being 3.1 × 1019 at/cm3 and 1.6 × 1019 at/cm3 for the high and low dose, respectively. The SIMS depth profiles of Cr for the Fe and W matrices established an ion implantation depth close to 2 μm on both substrates in agreement with the calculations previously performed by Stopping and Range of Ions in Matter (SRIM) simulations. Correlation between the integration of SIMS profiles and known concentrations of the implanted ion resulted in the calibration curve for each matrix, obtaining the SIMS quantification approach by means of this relative sensitivity factor (RSF). Additionally, a cross‐check of the method by comparing commercial Fe‐Cr alloys with the Cr‐implanted Fe matrices of the present study pointed out the need to produce standards with higher chromium concentrations. [ABSTRACT FROM AUTHOR]

In this work, a two‐dimensional (2D) waveguide on the 6.0 × 106‐eV C3+‐ion implanted RbTiOPO4 structure was prepared by the femtosecond laser under the manufacturing parameters of 3.0 μJ energy and 50.0 μm/s ablation velocity. The energy loss and damage profile were simulated by the SRIM 2013 for the irradiation with a fluence of 1 × 1014 ions/cm2. The end‐face and the surface of the 2D RbTiOPO4 crystal waveguide were characterized by a Nikon microscope. The refractive index profile and the near‐field intensity profile were studied by the ICM and the end‐face coupling technique, respectively. The RTP crystal 2D waveguide can well confine the light propagation and has the potentiality to serve as integrated photonic devices. [ABSTRACT FROM AUTHOR]

The surface morphology modification and optical property modification of semi-insulating gallium arsenide sample implanted with 100 keV silicon ions with the fluences ranging between 5 × 10 1 5 and 4 × 10 1 7 ion cm − 2 were analyzed using scanning electron microscopy and UV–Vis–NIR spectroscopy study. Scanning electron microscopy study revealed pore-like structure formation on the surface of gallium arsenide samples after silicon ion implantation. The size of these pore-like structures was found to increase with increasing ion fluence. Energy dispersive X-ray analysis showed an increase in silicon concentration in the gallium arsenide sample after silicon ion implantation with increasing ion fluence. The UV–Vis–NIR spectroscopy study revealed a decrease in optical transmission for silicon ion implanted gallium arsenide sample with increasing ion fluence. An additional absorption band was observed for the gallium arsenide sample implanted with the highest fluence (4 × 10 1 7 ion cm − 2). Urbach tail energy was found to increase with respect to ion fluence. [ABSTRACT FROM AUTHOR]

The economics and safety of reactors can be affected by the diffusion of fission products into graphite. Xenon (Xe) fission products diffusing into graphite is the most critical neutron absorber and poison that can slow down or stop the chain reaction. The transport parameters for inhibiting the xenon diffusion in graphite are therefore an important scientific problem. Self-sintered nanopore-isotropic (~40 nm) graphite (SSNG) derived from green pitch coke can decrease Xe diffusion into graphite. In this study, the surface morphology and microstructural evolution in graphite before and after irradiation, as well as after annealing, were studied with different characterization methods. A method for the measurement of diffusion coefficients of fission products' diffusion in graphite using Rutherford backscattering spectrometry (RBS) was also reported. The SSNG substrates were implanted with Xe at a dose of 4.8 × 1015 ions/cm2 and energy of 7 MeV. The RT-implanted samples were annealed in a vacuum at 650 °C for 9 h. The implanted and annealed samples were characterized using RBS. The diffusion coefficient D (Xe, 650 °C) was 6.49 × 10−20 m2/s. The results indicate SSNG's excellent ability to inhibit Xe diffusion and are significant for designing and evaluating the safety of nuclear reactors. [ABSTRACT FROM AUTHOR]

Ion implantation is performed in 4H-SiC with 11B, 27Al, 31P, 51V, 71Ga, and 75As ions using energies between 40 and 300 keV at various fluences along the [000-1] or the ⟨ 11 - 2 - 3 ⟩ axes. Secondary ion mass spectrometry is utilized to determine the depth distribution of the implanted elements. A Monte Carlo binary collision approximation (MC-BCA) code for crystalline targets is then applied to explain the influence of the electronic shell structure on electronic stopping and the obtained channeled ion depth distributions. The results show that, as the atomic number increases in a row of the periodic table, i.e., as the ionic radius decreases and the electron clouds densify, the interaction with the target electrons increases and the range is reduced. The decreased range is particularly pronounced going from 27Al to 31P. The reduction in channeling depth is discussed in terms of electronic shells and can be related to the ionic radii, as defined by Kohn–Sham. It is shown that these shell effects in channeled implantations can easily be included in MC-BCA simulations simply by modifying the screening length used in the local treatment of electronic stopping in channels. However, it is also shown that, for vanadium ions with an unfilled d-shell, this simple model is insufficient to predict the electronic stopping in the channels. [ABSTRACT FROM AUTHOR]

In this paper, we report light ion (H+) implantation-induced effect on a-plane GaN epitaxial layer on the sapphire substrate. Non-polar (NP) a-plane GaN (11–20) epitaxial layer is grown on an r-plane sapphire substrate by the metal–organic chemical vapour deposition (MOCVD) technique. The H+ ion-implanted NP (11–20) GaN epitaxial layer (dose 1 × 1017 cm−2 and 170 keV energy) is annealed by the rapid thermal annealing (RTA) process. The un-implanted a-GaN, H+ ion-implanted and annealed samples are investigated structurally and optically by High-resolution X-ray diffraction (HRXRD), Atomic force microscopy (AFM), Raman spectroscopy and Emission characterisation techniques. HRXRD analysis infers that implanted GaN sample is hydrostatically strained up to implanted depth. Raman scattering study by green laser excitation found defect-activated Raman scattering (DARS) due to lattice distortion by ion implantation in the implanted sample and annealed out partially after annealing. The Raman peak intensity ratio between the E2 (high) and LO peak of the above bandgap excited laser (~ 266 nm) was around 3.92 in the un-implanted GaN layer whilst after implantation, the ratio was reduced to ~ 0.97 because implantation induces the defect-activated centre which increased the LO peak intensity. After annealing, the ratio between E2 (high) and LO peak was increased by ~ 2.5. After annealing due to partial recovery and reduction in the implantation-induced defected activated centre, the a-plane GaN thin layer can be transferred to the other substrate easily by exfoliation or ion-cutting process and can be used in electronics and optoelectronic devices. [ABSTRACT FROM AUTHOR]

Gold nanoparticles (Au-NPs) were created in crystalline yttria-stabilized zirconia (YSZ). (100)-, (110)- and (111)-oriented YSZ samples were implanted by 1 MeV Au+ ions at room temperature and fluences ranging from 1.5 × 1016 cm−2 to 7.5 × 1016 cm−2. The prepared Au: YSZ structures were annealed at 1100 °C for 1 h on air to support the Au-NPs coalescence and YSZ structure recovery. Subsequent irradiation with the 10 MeV Si3+ ions with a fluence of 5.0 × 1014 cm−2 was performed to enable gradual modification of Au-NPs. Au-depth profiles and YSZ structure modification in the produced samples were analysed via Rutherford backscattering spectrometry in channelling mode (RBS-C) and X-ray diffraction (XRD). RBS-C showed the gold distributed in the region of about 50–300 nm below the YSZ surface. The disorder was accumulated in the region with Au-NPs and the concentration of the disorder increases as a function of ion implantation fluence. The Zr-disorder was partially decreased after the annealing, while the subsequent Si-ion irradiation increased Zr-disorder again, however, the disorder does not reach values before the annealing. XRD measurement evidenced elastic deformation of the YSZ host lattice in the Au-implanted samples. Optical absorbance showed the appearance of the new absorption band at 550 nm for the Au-ion fluences above 5.0 × 1016 cm−2 ascribed to the Au-NPs formation. After the annealing, the absorption band is shifted to the wavelength of 580 nm which could be connected to the proceeding clustering of Au. The maximum absorption peak intensity increases which is connected to the increasing amount of the Au-NPs. Transmission electron microscopy (TEM) with Energy dispersive spectroscopy (EDS) confirmed the presence of Au-NPs in the implanted layer after the annealing. The subsequent Si-ion irradiation did not change the Au-NP shape which remained spherical with a slight size increase. [ABSTRACT FROM AUTHOR]

Damage formation in 370 keV Kr ion-implanted BaWO4 is investigated with Rutherford backscattering spectrometry in channeling mode (RBS/C), performed in a quasi-in situ modus at a cryogenic temperature of 16 K. The obtained results are compared to those for similar experiments done previously at room temperature. The significant differences observed for ion implantation into BaWO4 at these two temperatures can be explained by the mobility of WO3 impurities. Other authors found WO3 to become mobile at temperatures above 240 K. This defect mobility can further account for the strong damage annealing occurring during warming implanted samples from 16 K to room temperature. In this temperature range, only completely amorphized layers remain stable. However, these layers transform into much less damaged layers exhibiting a strong crystalline long-range order during storage at room temperature with time, revealing a kind of self-healing. Another very important finding is the strong damage annealing due to the analyzing He ions during the RBS/C analysis both at 16 K and at room temperature. The analyzing He ions deposit their energy mainly in the electronic system of the target atoms. By applying an analytical thermal spike model, it is shown that the local temperature increase along the trajectory of the analyzing He ions could be responsible for observed damage annealing. The high susceptibility to energy deposition in electronic processes may have implications for any analysis based on energetic electrons. BaWO4 reveals a high radiation resistance at room temperature, which may be relevant for practical application. [ABSTRACT FROM AUTHOR]

The generation of p-type GaN through ion implantation is an attractive proposition in the massive production of GaN-based bipolar devices, whereas the removal of implantation induced lattice disturbances and defects is a difficult exercise and hampers the conversion of conductivity in GaN. Pulsed laser annealing is an effective annealing technique to recover lattice crystallinity and activate dopants with the preserved implanted profile. In this work, the effect of pulsed laser annealing on structural and optical recovery in high-dose magnesium (Mg) ion-implanted GaN has been investigated. The structural evolution and vibrational dynamics indicate an obvious structural recovery and partial strain release of Mg-implanted GaN during the pulsed laser annealing process, with a threshold laser fluence of 400 mJ/cm2, while rough surface structures are a result of the regrowth mechanism similar to liquid phase epitaxy. The enhanced donor–acceptor transition at 3.35 eV after pulsed laser irradiation is a sign of the effective activation of Mg from interstitial sites into the substitution of Ga ions. These results suggest that further optimization of the laser annealing technique has promising potential to manipulate the p-type conductivity of Mg-implanted GaN and to be implemented in GaN bipolar devices for practical applications. [ABSTRACT FROM AUTHOR]

The growth of GaN nanocrystals in an amorphous SiO2 matrix by sequential Ga and N implantation and rapid thermal annealing is reported. The effect of the implantation and annealing conditions on the distribution of the implanted ions, as well as the size, static disorder, and stability of the grown GaN nanocrystals, is studied by means of transmission electron microscopy, Rutherford backscattering spectrometry, Raman scattering, and extended X-ray absorption fine structure spectroscopies. It is found that the optimum temperature range for the post-implantation annealing of the nanocrystals, with a size that ranges from about 3 to 12 nm, is 1000–1100 °C. Higher temperatures result in the dissociation of the nanocrystals and out-diffusion of N and Ga, whereas lower temperatures are insufficient for the growth of GaN nanocrystals. Annealing for 30–90 s is optimum in order to avoid considerable loss of N and Ga. However, upon annealing at higher temperatures within the optimum range, up to 1100 °C, or for longer times, up to 120 s, larger GaN nanocrystals are grown and/or lower static disorder is observed. [ABSTRACT FROM AUTHOR]

Herein, carbon‐implanted high‐temperature annealed (HTA) AlN layers are analyzed and donor–acceptor pair (DAP) transitions probably between the two most abundant impurities, carbon and oxygen, are identified. Both are regarded as the main, hard‐to‐avoid impurities in crystal growth. Oxygen is believed to lead to absorption in the deep UV below a wavelength of 250 nm. In contrast, carbon is the most likely candidate to be responsible for a distinct absorption band around 265 nm. This interpretation has recently been challenged. In this study, carbon‐implanted and HTA AlN layers with ion fluences above 8.1 × 1015 cm−2 are analyzed using low‐temperature and time‐resolved cathodoluminescence spectroscopy. Due to the high concentration of oxygen inside the AlN, as a result of the HTA process, a DAP transition between a most likely carbon‐related acceptor and ON is observed. The measured temperature‐ and power‐dependent blueshift of the peak emission energy as well as the luminescence transients can be clearly explained by a continuous change from a DAP transition at low temperature to a free electron to acceptor transition with increasing temperature. The findings are supported by a configurational coordinate model that describes the measured behavior qualitatively. [ABSTRACT FROM AUTHOR]

This paper studies Au-nanoparticles' (AuNPs) formation in titanium dioxide (TiO 2) by ion implantation. Samples of TiO 2 thin films deposited on glass and silicon were prepared using magnetron sputtering. Ion implantation was used to create the AuNPs, with fluences ranging from 2.0 × 101⁶ to 4.0 × 1017 ions/cm2. Each sample was implanted with 50 and 100 keV to achieve a broader in-depth distribution of Au. A post-implantation thermal treatment, at 500˚C, was applied, during 15 min, to promote precipitation of the implanted Au. Using Rutherford backscattering spectrometry, the elemental depth profiles were analysed before and after annealing. The X-ray diffraction analysis revealed the presence of the (1 1 1) Au diffraction peak, and the microstructure analysis, using scanning electron microscopy confirmed the presence of NPs. The optical transmission data, shows a band around 600–650 nm, for the samples implanted with 1.6 × 1017 and 4.0 × 1017 ions/cm2. [ABSTRACT FROM AUTHOR]

Silicon layers with a selenium impurity concentration up to 1021 cm–3, which exceeds the equilibrium solubility limit of this impurity in silicon by four orders of magnitude, were obtained by high-dose ion implantation followed by pulsed laser annealing at pulse energy densities from 0.5 to 2.5 J/cm2. Rutherford backscattering of He+ ions showed that up to 70% of the implemented impurity atoms were localized at silicon crystal-lattice sites after laser annealing. The Se-hyperdoped Si layers were characterized by increased (up to 45–55%) absorption in the spectral range 1100–2400 nm. Thermal treatment (550°C for 30 min followed by 850°C for 5 min) did not increase the IR absorption as compared with the initial Si, which was explained by Se losses resulting from diffusional redistribution. Recrystallization of Si layers amorphized by Se ions and redistribution of the dopant with equilibrium thermal treatment were theoretically evaluated. [ABSTRACT FROM AUTHOR]

There has been a long interest in the analysis of radiation damage caused by ion beams due to their presence in space or the nuclear industry and their application in materials modification. One of the methods used for that purpose is Rutherford Backscattering Spectrometry in channeling mode (RBS/C). However, the presence of different defect types makes it difficult to interpret RBS/C spectra so extended defects are often neglected in the data analysis. The McChasy Monte Carlo simulation code has been developed to analyze channeling data in crystals containing different defect types using periodically repeated relatively small simulation cells (∼102 atoms). Here we report and describe its recent feature: a model of dislocation loops. Having in mind that the interactions of the channeling ion beam with defects depend on the beam energy, the validity of the model was confirmed by analyzing RBS/C experiments performed at different energies for the case of 300 keV Eu-implanted GaN. [ABSTRACT FROM AUTHOR]

Semiconductor nanocrystals incorporated in a dielectric film are widely studied as potential candidates to exceed the Shockley-Queisser theoretical conversion limit of photovoltaic cells. In this context, Ge nanocrystals embedded in SiO 2 films seem to be among the best candidates. However, the charges generated in the dielectric film are hard to collect. For this reason, it would be better if the charges were generated in a semiconductor matrix such as silicon, which has better conductivity. However, implanted Ge atoms have poor mobility in a silicon matrix and thus Ge nanocrystals formation is not likely. But even if the formation of Ge nanocrystals seems difficult, it would still be interesting to form crystalline Si 1-x Ge x alloys. This work investigates the formation of the Si 1-x Ge x films by ion implantation and their crystallinity. 36 keV Ge ions were implanted in crystalline Si substrates, with fluences ranging from 5 × 1015 to 1.5 × 1017 Ge/cm2 at temperatures up to 600 °C. Rutherford Backscattering Spectrometry (RBS), Raman Spectroscopy, and Transmission Electron Microscopy (TEM) were used to investigate the microstructure of the Si 1-x Ge x alloys. It is shown that germanium is mostly incorporated in the crystal network in substitutional sites. XRD, Raman spectroscopy, and TEM confirm that the Si 1-x Ge x layer on top of the c-Si substrate is monocrystalline. TEM also indicates the possible presence of nanostructures, extended defects or both. Implantation was also carried out at temperatures up to 600 °C, with the objective of preserving the crystallinity and promoting Ge diffusion into nanoclusters. RBS shows that the Ge profile is more extended in depth for the sample implanted at 600 °C, compared to a room temperature implantation. As the energy of the ions is the same in both samples, this indicates that Ge is able to diffuse in depth during the implantation at 600 °C compared to implantation at ambient temperature. However, RBS/C shows that the minimal yield is higher for the implantation at 600 °C, indicating a high concentration of interstitials or that crystallinity is deteriorated, as confirmed by TEM. [ABSTRACT FROM AUTHOR]

Rare earth-doped zinc oxide (ZnO:RE) systems are attractive for future optoelectronic devices such as phosphors, displays, and LEDs with emission in the visible spectral range, working even in a radiation-intense environment. The technology of these systems is currently under development, opening up new fields of application due to the low-cost production. Ion implantation is a very promising technique to incorporate rare-earth dopants into ZnO. However, the ballistic nature of this process makes the use of annealing essential. The selection of implantation parameters, as well as post-implantation annealing, turns out to be non-trivial because they determine the luminous efficiency of the ZnO:RE system. This paper presents a comprehensive study of the optimal implantation and annealing conditions, ensuring the most efficient luminescence of RE3+ ions in the ZnO matrix. Deep and shallow implantations, implantations performed at high and room temperature with various fluencies, as well as a range of post-RT implantation annealing processes are tested: rapid thermal annealing (minute duration) under different temperatures, times, and atmospheres (O2, N2, and Ar), flash lamp annealing (millisecond duration) and pulse plasma annealing (microsecond duration). It is shown that the highest luminescence efficiency of RE3+ is obtained for the shallow implantation at RT with the optimal fluence of 1.0 × 1015 RE ions/cm2 followed by a 10 min annealing in oxygen at 800 °C, and the light emission from such a ZnO:RE system is so bright that can be observed with the naked eye. [ABSTRACT FROM AUTHOR]

A monocrystalline rutile (TiO2) plate implanted with cobalt ions at a fluence of 1.25∙1017 ions/cm3 with energy 40 keV at constant current density in the ion beam of 2 μA/cm2 when the temperature of the irradiated substrate was maintained at 620°C was studied using light reflection and transmission spectroscopy in the visible spectral region. The spectral dependences of the optical parameters of the modified layer were obtained. The calculated optical Tauc gap of the layer was 0.2–0.3 eV. [ABSTRACT FROM AUTHOR]

Potassium tantalite (KTaO 3) has shown an excellent performance in optoelectronic applications, proving its advantages with respect to fabricating single crystal thin films by ion implantation. This work introduces the damage formation of KTaO3 under 200 keV He ion implantation at room temperature and He bubbles accumulation. Ion implantation-induced lattice damage before and after annealing was quantitatively analyzed by using the Rutherford backscattering spectrometry in channeling technique. The crystals phase analysis of the samples under different fluences was studied by using the X-ray diffraction technique. For 200 keV He ions, the accumulation and migration of He bubbles were induced by the thermal annealing effect under high fluences of He + . The He bubbles appear obviously coarsening and embrittlement with thermal annealing. The blistering phenomenon caused by He ion implantation is the physical basis for the smart-cut technique, which allows the preparation of high-quality single-crystal films. [ABSTRACT FROM AUTHOR]

A two-dimensional waveguide is the building block in integrated photonic circuits. In this work, the 5.0 MeV oxygen ion implantation at a dose of 5. 0 × 1 0 1 4 ions/cm2 was carried out on the fused silica glass for the formation of the planar waveguide. Then, a femtosecond laser was employed to ablate the ion-implanted surface at a speed of 200 μ m/s for the construction of the ridge waveguide. The energy depositions of the oxygen ion implantation into the fused silica glass were simulated by the SRIM 2013. The microscopic morphology of the ridge waveguide was photographed by a Nikon microscope. The near-field intensity distributions of the ridge waveguide at 532 nm and 976 nm were measured by using the end-face coupling system. The ion-implanted and femtosecond-ablated ridge waveguide on the fused silica glass has the potential as a photonic device for integrated optical systems at the visible and near-infrared bands. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ar, C, and Fe low energy and low fluence Ion implantation for 2DEG electrical isolation. • Defects creation by ion implantation in AlGaN/GaN heterostructure. • 2DEG AlGaN/GaN high electron mobility transistor (HEMT). • Non-radiative recombination centers produced by Ion bombardment. • High thermal stability of 2DEG isolation by ion implantation. • Defects diffusion towards AlGaN surface. We report a comparative study of the isolation mechanisms of two-dimensional electron gas (2-DEG) in Al 0.2 Ga 0.8 N/GaN heterostructure by room temperature ion implantation with Ar, C or Fe at 15, 20, 18 keV and fluences of 7 × 1013, 1 × 1014, 5 × 1013 cm−2, respectively. The samples were annealed up to 900 °C post-implantation and characterized by X-ray Diffraction, X-ray Photoelectron Spectroscopy, Photoluminescence, Rutherford Backscattering Spectrometry in Channeling mode and Capacitance Voltage profiling. The ion implantation produces unrecoverable crystal lattice damage such as point defects and non-radiative carrier traps level into the band gap of GaN. As a consequence, a decrease in the number of occupied states at the upper side of the valence band of GaN was observed. Moreover, defects accumulation at the near-surface region by annealing at 900 °C was observed. Due to the various defects, the concentration of 2-DEG carriers, after ion implantation, for all three ions investigated, is reduced from 1019-1020 to less than 1013 ––1014 cm−3. The 2-DEG isolation was stable up to 900 °C for all three ions, while the non-radiative defects and carrier traps produced were slightly more stable in the case of Fe implantation. The reduction of carrier concentration is responsible for the isolation of 2-DEG. [ABSTRACT FROM AUTHOR]

Achieving extremely low specific contact resistance (ρ c) has become a critical challenge for nanoelectronics to achieve high device performance with increased miniaturization. In this work, we explore the use of Tellurium hyperdoping and millisecond-range post-metallization flash lamp annealing as a potential solution to overcome this bottleneck. The epitaxially-resolidified hyperdoped Si layers with tunable carrier densities approaching 1021 cm−3 are achieved, which consequently alters the band diagrams as simulated by COMSOL Multiphysics®. This results in a sufficiently narrow Schottky barrier, which enables electron tunneling and can ultimately achieve extremely low ρ c on the order of 10−9 Ω·cm2 in an Au/Ti/Te-hyperdoped Si junction. This study introduces an alternative fabrication process for Schottky barrier engineering, providing a viable method for the realization of future miniaturized nanoelectronics devices with high carrier density and extremely low ρ c. [Display omitted] [ABSTRACT FROM AUTHOR]

Modifying bandgap by ion implantation based defect-engineering is a widely used technique for electronic and optoelectronic device fabrications. This report studies the influence of defect on bandgap modification in MgO single-crystal by MeV Co ion implantation in the fluence range of 5 × 10 14 to 1 × 10 16 ions/cm 2 . The substitutional defects, F and V type color centers have been identified and characterized from optical absorption and photoluminescence spectra. We elucidated a mechanism of the electronic transition from F centers to conduction band via F + center and subsequent de-excitation. The F center concentration increases with ion fluences while the bandgap obtained from the Tauc plotting gradually decreases. The band structure and density of states of different defects associated with MgO after ion implantation were calculated using density functional theory to explain the experimental bandgap modifications. [ABSTRACT FROM AUTHOR]

Thick (0.125 mm) sheet samples of PET were irradiated with 150 keV Cs+ ion beam with fluences in the range from 1013 cm-2 up to 1016 cm-2). Raman and UV-VIS spectroscopy measurements shown destruction of numerous bonds within the polymer – this effect intensifies with fluence. Raman spectroscopy shows the presence of amorphous graphitelike structures as the broad G band appears in the collected spectrum. The analysis of absorbance spectra also confirms formation of numerous carbon clusters leading to a formation of vast conducting structures in the modified layer of the polymer. One can observe the decrease of optical bandgap from 3.85 eV (typical for pristine PET) to 1.05 eV for the sample implanted with the highest fluence, the effect is weaker than for lighter alkali metal ions. The estimated average number of C atom in a clusters reaches in such case values close to 1100. The changes in the polymer structure lead to intense reduction of electrical sheet resistivity of the modified samples by ~ 8 orders of magnitude in the case of severely modified sample. The dependence of resistivity on temperature has also been measured. The plots of ln(σ) vs 1/T show that band conductivity or nearest neighbor hopping between conducting structures prevail in the considered case. [ABSTRACT FROM AUTHOR]

Rare earth (RE) elements are important for the optical tuning of wide bandgap oxides (WBO) such as β-Ga2 O3 or ZnO, because β-Ga2 O3 :RE or ZnO:RE show narrow emission lines in the visible, ultra-violet and infra-red region. Ion implantation is an attractive method to introduce dopant into the crystal lattice with an extraordinary control of the dopant ion composition and location, but it creates the lattice damage, which may render the dopant optically inactive. In this research work, we investigate the post-implantation crystal lattice damage of two matrices of wide-bandgap oxides, β-Ga2 O3 and ZnO, implanted with rare-earth (RE) to a fluence of 5×1014, 1×1015 and 3×1015 atoms/cm², and post-growth annealed in Ar and O2 atmosphere, respectively. The effect of implantation and annealing on both crystal lattices was investigated by channeling Rutherford backscattering spectrometry (RBS/C) technique. The level of crystal lattice damage caused by implantation with the same RE fluences in the case of β-Ga2 O3 seems to be higher than in the case of ZnO. Low temperature photoluminescence was used to investigate the optical activation of RE in both matrices after performed annealing. [ABSTRACT FROM AUTHOR]

A competitive new technology, organic metallic halide perovskite solar cells feature a wide working area, low manufacturing costs, a long lifespan, and a significant amount of large efficacy of power conversion (PCE). The spin-coating technique was utilized for the fabrication of pure CH3NH3PbBr3 (MAPbBr3) thin films, and these films are implanted with 600 keV silver (Ag) ions at fluency rate of 6 × 1014 and 4 × 1014 ions/cm2. XRD analysis confirmed the cubic structure of MAPbBr3. A high grain size was observed at the fluency rate of 4 × 1014 ions/cm2. The UV-Vis spectroscopic technique was used to calculate the optical properties such as the bandgap energy (Eg), refractive index (n), extinction coefficients (k), and dielectric constant. A direct Eg of 2.44 eV was measured for the pristine film sample, whereas 2.32 and 2.36 eV were measured for Ag ion-implanted films with a 4 × 1014 and 6 × 1014 ions/cm2 fluence rate, respectively. The solar cells of these films were fabricated. The Jsc was 6.69 mA/cm2, FF was 0.80, Voc was 1.1 V, and the efficiency was 5.87% for the pristine MAPbBr3-based cell. All of these parameters were improved by Ag ion implantation. The maximum values were observed at a fluency rate of 4 × 1014 ions/cm2, where the Voc was 1.13 V, FF was 0.75, Jsc was 8.18 mA/cm2, and the efficiency was 7.01%. [ABSTRACT FROM AUTHOR]

• Intermixing of layers at the interface and exchange of atoms within multilayer stack was not observed. • Formation of metal hydride with stoichiometry TiH 2. • Enhance stability of the system in the presence of pure H 2 gas. • Entrapment of the H atoms by the implanted species. • Ineffectiveness of Fe and Mg ion implantation in the enhancement of H absorption. The effect of implanted 150 keV Fe ion and 100 keV Mg ions on hydrogen (H) absorption by Pd/Ti/V/Pd/Ti multilayer films, prepared on Ti substrate, was investigated using the H profiling analytical technique, energy recoil detection analysis (ERDA). The stability of the multilayer stack system at 550 °C was investigated using Rutherford backscattering spectrometry for the investigation of possible intermixing of layers and X-ray diffraction for crystal structure and any possible new phase formation due to elevated temperatures. SEM was used for surface topography investigation. Ion penetration, distribution, and vacancy distribution inside the system, under investigation, were achieved using the Monte Carlo semi-empirical simulation code, Stopping and Range of Ions in Matter, and found to be 700 and 1055 Å for 150 keV Fe ions and 100 keV Mg ions implantations, respectively. ERDA revealed a maximum H amount of ∼ 4.8 at.% at a depth of ∼ 1.8 µm, with ∼ 2.6 at.% average H content over the probed depth in the non-implanted hydrogenated sample. The average H amount values in the 150 keV Fe ions implanted samples, over a probed depth, were found to be ∼ 1.32, ∼1.19 and ∼ 1.09 at.% in samples implanted up to a fluence of 1 × 1014, 1 × 1015, and 1 × 1016 ions/cm2, respectively, with H content, restricted to the surface and near the surface and constantly decreased into the bulk. The average H amount values, over a probed depth, in the 100 keV Mg ions implanted samples, up to 1 × 1014, 1 × 1015, and 1 × 1016 ions/cm2 fluence, were found to be ∼ 1.26, ∼1.25, and ∼ 1.17 at.%, respectively. These results suggest the entrapment of the H atoms by the implanted species and the ineffectiveness of Fe and Mg ion implantation in the enhancement of H absorption and diffusion in these films; at least at the energies and fluence used in this investigation. No indication of intermixing, suggesting that the system was stable up to 500 °C in an H 2 environment. [ABSTRACT FROM AUTHOR]

Due to its unique material properties, such as extreme hardness and radiation resistance, silicon carbide has been used as an important construction material for environments with extreme conditions, like those present in nuclear reactors. As such, it is constantly exposed to energetic particles (e. g., neutrons) and consequently subjected to gradual crystal lattice degradation. In this article, the 6H-SiC crystal damage has been simulated by the implantation of 4 MeV C3+ ions in the (0001) axial direction of a single 6H-SiC crystal to the ion fluences of 1.359-1015 cm-2, 6.740-1015 cm-2, and 2.02-1016 cm-2. These implanted samples were subsequently analyzed by Rutherford and elastic backscattering spectrometry in the channeling orientation (RBS/C & EBS/C) by the usage of 1 MeV protons. Obtained spectra were analyzed by channeling simulation phenomenological computer code (CSIM) to obtain quantitative crystal damage depth profiles. The difference between the positions of damage profile maxima obtained by C SIM code and one simulated with stopping and range of ions in matter (SRIM), a Monte Carlo based computer code focused on ion implantation simulation in random crystal direction only, is about 10 %. Therefore, due to small profile depth shifts, the usage of the iterative procedure for calculating crystal damage depth profiles is proposed. It was shown that profiles obtained by iterative procedure show very good agreement with the ones obtained with CSIM code. Additionally, with the introduction of channeling to random energy loss ratio the energy to depth profile scale conversion, the agreement with CSIM profiles becomes excellent. [ABSTRACT FROM AUTHOR]

Porous Ge layers consisting of nanowires were formed by low‐energy high‐dose implantation of monocrystalline c‐Ge substrate with Ag+ and Cu+ ions. The obtained layers were studied by Raman spectroscopy using solid‐state and He‐Ne exciting lasers with wavelength of 532 and 633 nm, respectively. The crystalline volume fraction and local temperature of porous layers at the surface sites of laser probing were determined. To interpret the change in the shape of the spectra under the action of laser radiation, deconvolution into amorphous and nanocrystalline components was carried out. Analysis of the spectral line shape made it possible to estimate the crystalline and amorphous volume fractions. The quantum confinement model for Ge nanocrystallites was taken into account for accurate estimations of volume fractions. These estimates showed that the implanted amorphous layers of all samples were locally crystallized with a solid‐state laser. He‐Ne laser excitation resulted in partial crystallization only for layers obtained by Cu+ ion implantation. The measured ratio of the Stokes to anti‐Stokes components demonstrated that the porous layers obtained by implanting Ag+ ion were not heated by a He‐Ne laser and according to the analysis of spectral lines, the crystalline volume fraction did not appear in these layers during probing. The results obtained are explained by the difference in the penetration depth for various samples of the exciting radiation. [ABSTRACT FROM AUTHOR]

In this study, the effect of swift heavy ions (SHIs) irradiation in the recrystallization of polycrystalline SiC pre-implanted with selenium (Se) ions and migration of Se was investigated. The main objective of this study is to investigate the role of SHIs with the maximum electronic energy loss greater than 20 keV/nm on structural evolution of initially amorphized pre-implanted SiC and the migration of pre-implanted fission products (FPs). The pristine SiC samples were first implanted with 200 keV Se ions to a fluence of 1 × 1016 cm−2 at room temperature (RT) and at 350 °C. Some of the pre-implanted samples were then irradiated with bismuth (Bi) ions of 710 MeV to a fluence of 1 × 1013 cm−2 at RT. The characterization of both the implanted and implanted then irradiated SiC was conducted using techniques such as transmission electron microscopy (TEM), Raman spectroscopy, scanning electron microscopy (SEM), and Rutherford backscattering spectrometry (RBS). At RT, Se ions implantation caused the amorphization of SiC to a depth of about 187 nm beneath the surface. In contrast, when implanted at 350 °C, the SiC retained its crystalline structure with some defects (i.e., point defects, point defect clusters and some dislocation loops). The SHIs irradiation of the RT implanted SiC resulted in the reduction of the amorphous layer thickness from 187 nm to around 178 nm and led to the formation of nanocrystalline SiC in the amorphous layer. Irradiation of the SiC implanted at 350 °C induced some crystallization of defects. Notably, no evidence of Se ions migration was observed in both the irradiated RT-implanted and the hot-implanted SiC. • Polycrystalline SiC substrates were implanted with Se ions of 200 keV to a fluence of 1 × 1016 cm−2 at room temperature (RT) and 350 °C, subsequently some samples were irradiated with710 MeV Bi+51 (maximum electronic energy loss of 33.7 keV/nm) to fluence of 1 × 1013 cm−2 at RT. • At RT, the implantation of the ions caused amorphization in SiC, whereas implantation at 350 °C maintained its crystalline structure with some defects. • The SHIs irradiation of RT pre-implanted SiC led to the formation of nanocrystalline SiC in the amorphous layer. While irradiation of the SiC implanted at 350 °C induced some crystallization of defects. • There was no migration of the implanted Se ions was detected after exposing both RT and 350 °C pre-implanted SiC to 710 MeV Bi+51 irradiation with maximum electronic energy loss of about 33.7 keV/nm. [ABSTRACT FROM AUTHOR]

Cupric oxide is a semiconductor with applications in sensors, solar cells, and solar thermal absorbers. To improve its properties, the oxide was doped with a metallic element. No studies were previously performed on Cr-doping using the ion implantation technique. The research goal of these studies is to investigate how Cr ion implantation impacts the properties of the oxide thin films. CuO thin films were deposited using magnetron sputtering, and then chromium ions with different energies and doses were implanted. Structural, optical, and vibrational properties of the samples were studied using X-ray diffraction, X-ray reflectivity, infra-red spectroscopy, Raman spectroscopy, and spectrophotometry. The surface morphology and topography were studied with ellipsometry, atomic force microscopy, and scanning electron microscopy. A simulation of the range of ions in the materials was performed. Ion implantation had an impact on the properties of thin films that could be used to tailor the optical properties of the cupric oxide and possibly also its electrical properties. A study considering the influence of ion implantation on electrical properties is proposed as further research on ion-implanted CuO thin films. [ABSTRACT FROM AUTHOR]

We investigated the ellipsometer-based characterization method being used to quickly evaluate the depth of the damage layer in ion-implanted 4H-SiC. This method had the advantages of low cost, convenience, and non-destructiveness. Optical absorption of n-type 4H-SiC substrate, P+ ion-implanted, laser-annealed, and conventional high-temperature annealed wafers were investigated at room temperature. Three peaks were observed in the absorption spectra collected for various samples. The degree of electrical activation after laser annealing or high-temperature annealing was evaluated qualitatively from the absorption peak intensity at 2.67 eV. The circular transmission line method (CTLM) results were consistent with the optical absorption results. However, it was found that the effective carrier concentration after laser annealing was significantly lower than that after high-temperature annealing. [ABSTRACT FROM AUTHOR]

Very high fluence implantation of 14 N + ions was used to promote the formation of a nitride layer on the surface of steel coinage dies used by the Portuguese Mint. Die steel samples were studied before and after implantation at 90 keV plus 30 keV for two nominal fluences, 5.0 × 10 17 at/cm 2 and 1.0 × 10 18 at/cm 2 , and for two implantation temperatures, room and liquid nitrogen temperature. Surface characterization was carried out by ultramicrohardness indentation, Atomic Force Microscopy (AFM), and Rutherford Backscattering Spectrometry (RBS). A significant increase (factor two) in depth reached by the implanted nitrogen was observed for LN2 implantations, which, to our knowledge, was never reported before. Results point out the benefit of nitrogen implantation at room temperature with a nominal fluence of 5.0 × 10 17 at/cm 2 , which raised the hardness of the dies by ∼40% (from 6.2 ± 0.5 to 8.7 ± 0.7 GPa). Nitrogen implanted dies were used to mint circulating two cents euro coins and their performance was assessed, showing that when compared to Vautrol coated dies (standard coating used by the Portuguese Mint), the crack density was lower and similar wear resistance was observed. [ABSTRACT FROM AUTHOR]

The electrically detected orbital spectrum of a mesoscopic silicon device containing a small number of donors has been investigated. The device was fabricated on silicon-on-insulator with an optically active channel containing 6 × 10 5 substitutional bismuth centers introduced by ion implantation. The 1 s (A 1) → 2 p ± orbital transition at the energy associated with isolated bismuth donors was detected via a change in photocurrent when illuminated by THz light from a free electron laser. The spectral dependence on bias, temperature, and laser intensity is explored to determine optimum conditions for detecting orbital transitions in smaller devices with fewer donors. These results suggest that photo-induced impact ionization can offer a route for the spectroscopic detection of few impurities providing a useful tool for the development of solid-state quantum technologies. [ABSTRACT FROM AUTHOR]

This paper analyzes the effect of 100 keV silicon negative ion implantation in semi-insulating gallium arsenide sample for the fluences varying between 1 × 1 0 1 5 and 2 × 1 0 1 7 ion cm − 2 using Raman spectroscopy, Rutherford backscattering spectroscopy and Electron spin resonance spectroscopy. The gallium arsenide sample implanted with silicon negative ion for different fluences showed shift in the TO peak position with respect to unimplanted gallium arsenide sample. Increase in the broadening of TO peak was observed in the as-implanted samples, indicating development of stress and phonon confinement due to the incorporation of silicon in gallium arsenide crystal lattice. Annealing of as-implanted samples showed stress relaxation. Increase in RBS backscattering yield was observed in the as-implanted samples. Annealing of as-implanted (with high fluence) sample showed flat RBS yield response. ESR measurement study revealed restructuring of defects in the gallium arsenide sample implanted with fluence of 1 × 1 0 1 7 ion cm − 2 after annealing to the temperature of 3 0 0 ∘ C. [ABSTRACT FROM AUTHOR]

The influence of magnetic dopants on the transport properties of topological insulators is of great interest. In this work, studies on the impact of Fe− ion implantation on the physical and electronic properties of Sb2Te3 thin films have been done. The implantation was done with low-energy Fe− ions at three different fluences (1 × 1013, 1 × 1014, and 5 × 1014 ions/cm2). The film thickness was estimated using Rutherford backscattering spectroscopy (RBS). Magnetic force microscopy (MFM) topographic image showed the Fe− ion-induced magnetization in thin films. Overall enhancement in the electrical resistivity with increasing implantation dose was observed in the temperature-dependent transport measurements. However, the mobility of the carriers was found to decrease with increasing fluence. The Hall measurements showed that the carrier concentration initially increased with the fluence up to 1 × 1014 ions/cm2, but further increase in the fluence results in a decrease in the carrier concentration. P-type nature of the dominant charge carriers was observed for all the fluences except the highest dose where a change in the type of carriers from p-type to n-type was observed. It can be explained based on Fe− ion implantation-induced donors as well as acceptors like defects. [ABSTRACT FROM AUTHOR]

Single crystals of semi-organic potassium hydrogen phthalate crystals and l-proline(LP) amino acid (0.5 mol%)-doped potassium hydrogen phthalate crystals were implanted with 10 keV Ar+ ions at various fluencies of 1 × 1015, 5 × 1015, 1 × 1016, and 5 × 1016 ions/cm2 to enhance their nonlinear optical property. Pure KHP, L-proline (0.5 mol%), and Ar+ ion-irradiated samples were characterized by single-crystal X-ray diffraction, powder X-ray diffraction, UV–visible spectroscopy, photo luminescence spectroscopy, microhardness testing, dielectric study, and non-linear optical (NLO) behavior. The study reveals that the Ar+ ion irradiation led to physical and chemical changes which altered the mechanical and optical properties of the samples. The l-proline-doped KHP showed an improved second-harmonic generation (SHG) efficiency compared to the KHP Ar+ ion-irradiated crystals. The energy deposition by the ion beam in the sample was studied by simulations using SRIM-2013 program. The study reveals that the Ar+ ion irradiation indicated the role of defects which could have influenced the non-linear optical behavior. Theoretical values of SHG calculated using the Python computational package indicate that further increase of Ar+ ion fluence will increase the SHG in l-proline (0.5 mol%)-doped KHP crystal. Further, it was prognosticated that beyond the Ar+ ion fluence of 1.9 × 1017 ions/cm2, the crystal size diminished. [ABSTRACT FROM AUTHOR]

The freely available "Stopping and Range of Ions in Matter" (SRIM) code is used for evaluating ion beam ranges and depth profiles. We present secondary ion mass spectrometry and Rutherford backscattering experimental results of Si samples implanted with low energy Sb ions to evaluate the accuracy of SRIM simulations. We show that the SRIM simulation systematically overestimates the range by 2–6 nm and this overestimation increases for larger ion implantation energy. For the lowest energy implantation investigated, here we find up to a 25% error between the SRIM simulation and the measured range. The ion straggle shows excellent agreement between simulation and experimental results. [ABSTRACT FROM AUTHOR]

Layers of selenium-hyperdoped silicon with dopant concentration of up to (4–6) × 1020 cm–3 that exceeds the limit of equilibrium solubility of this impurity by 4 orders of magnitude were obtained using ion implantation followed by pulsed laser annealing (PLA) at pulse energy densities of W = 0.55, 0.8, 1.0, 1.5, 2.0, and 2.5 J/cm2. Rutherford back scattering of helium ions demonstrated that up to 60–70% of introduced impurity occupied silicon lattice sites. Selenium-hyperdoped layers exhibited substantial absorption (36–40%) in the wavelength range of 1100–2400 nm. Absorption spectra of silicon layers obtained at different regimes of laser annealing are compared with each other. It is demonstrated that annealing at W = 2.0 J/cm2 is optimal from the point of view of achieving maximum structural perfection of hyperdoped silicon layers. This factor is very important for application of formed structures in photodetectors and components of solar energy systems. At the same time, absorption in the visible and near IR wavelength ranges attained maximum value after annealing at W = 1.0 J/cm2 and remained nearly unchanged with further increase in the pulse energy density. [ABSTRACT FROM AUTHOR]

200 nm thick SiO2 layers grown on Si substrates were implanted with 150 keV Ge ions at three different fluences. As-implanted samples were characterized with time-of-flight secondary ion mass spectrometry and Rutherford backscattering spectrometry to obtain depth profiles and concentration of Ge ions. As-implanted samples were annealed at 950 °C for 30 min. Crystalline quality of pristine, as-implanted, and annealed samples was investigated using Raman scattering measurements and the results were compared. Crystalline structure of as-implanted and annealed samples of embedded Ge into SiO2 matrix was studied using x-ray diffraction. No secondary phase or alloy formation of Ge was detected with x-ray diffraction or Raman measurements. Scanning transmission electron microscope measurements were done to get the nanocrystal size and localized information. The results confirmed that fluence dependent Ge nanocrystals of different sizes are formed in the annealed samples. It is also observed that Ge is slowly diffusing deeper into the substrate with annealing. [ABSTRACT FROM AUTHOR]

Ion accelerators have a fundamental role in atomic and nuclear studies as well as in applied physics, including the modification and characterization of materials. The precise knowledge of the energy of accelerated ions is of utmost importance, especially for cross-section measurements or for accurate depth profiling using narrow resonances. The 3 MV Cockcroft–Walton tandem accelerator of IFIN-HH from HVEC was installed in 2012. The machine is mainly dedicated to ion beam analysis, ion implantation, and astrophysics studies at low energy. In this work, we report on the first calibration for alpha particles of the terminal voltage using a technique based on Rutherford backscattering spectrometry measurements. The energies of the α particles from a mixed spectroscopic 239Pu + 241Am α source are compared with the energies of 4He projectiles backscattered into a silicon detector by carbon and gold layers. The position of the 16O(α,α) 16O resonance around 3.038 MeV at backscattering angles of 145° and 165° was remeasured. Our results are compared with recent results reported in the literature. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ion-induced nanoscale patterning strongly reduces optical reflectance of Ge surface. • The antireflection is over ultraviolet–visible-infrared wavelength range. • When saw-tooth-like nanostructures evolve, the Ge surface behaves effectively like a black-Ge. • Antireflection results from a gradient in refractive index at Ge surface. • The ion-patterned surfaces are hydrophobic because of change in surface free energy. Designing materials surfaces for reducing the reflection of light is imperative towards enhancing the performance of optical and optoelectronic devices. We show that ion implantation under specific experimental conditions is a single step and controllable process to minimize reflection over a large wavelength range by growth of surface nanostructure in a self-organized fashion. For instance, we show a strong reduction in optical reflectance in the ultraviolet–visible-infrared wavelength range (300–3000 nm) for Ge with the evolution of nanoscale self-organized patterns under energetic ion bombardment at oblique angles. As pattern coarsening takes place with increasing ion fluence (for subtle incident angles), the optical reflectance reduces to a significant extent. The evolution of saw-tooth-like structures on Ge surface, at an oblique incidence of 60° to the fluence of 3 × 1018 ions cm−2, leads to a huge reduction in optical reflectance (below 4% over a wide spectral range) and makes it behave effectively like a black-Ge specimen. The huge reduction in the optical reflectance is found to be related to the dimension of the surface features evolved under ion implantation at room temperature. The observed surface morphology gives rise to an effective gradient in refractive index from the top toward the bottom of the patterned surface. Thus, the reduction in refractive index is calculated and correlated with the respective surface morphology. We have also studied change in the wetting property of ion-induced patterned surfaces and correlated it with the reduction in surface free energy due to the presence of oxygen. [ABSTRACT FROM AUTHOR]