Transition In Si Research Articles

Atomistic understanding of ductile-to-brittle transition in single crystal Si and GaAs under nanoscratch

Ensuring ductile removal in a grinding process is crucial for achieving the desired finish on a hard and brittle single crystal. This study provides new insights into the material removal processes in Si and GaAs single crystals, exploring their deformation behaviour using Berkovich and Conical tips to replicate contact from a fixed abrasive grit. Experimental observations are compared with Molecular Dynamic (MD) simulations to uncover the atomistic deformation mechanisms during the ductile-to-brittle transition (DBT). Notable plastic deformation and minimal cracking were consistently observed in Si, irrespective of the tips used. MD simulations supported this observation, revealing pronounced chip formation indicative of ductile material removal. The resistance to cracking in Si was attributed to amorphization induced by localized high contact stresses. In contrast, GaAs showed a propensity for cracking, with MD simulations revealing dislocation and slip band formation, and cracks emerging in the areas of substantial plastic deformation. These findings address phenomena not previously discernible in experimental studies due to the challenge of real-time observation. Moreover, the tip geometry was shown to significantly influence stress distribution, impacting deformation and crack formation in GaAs. This study also reveals limitations in predicting the critical depth for DBT in both Si and GaAs throught the amended Bifano, Dow, and Scattergood (aBDS) models and MD simulation, offering nuanced insights into these challenges that have not been extensively explored. It was found that the experimental results exceeded predictions by an order of magnitude. These discrepancies underscore the aBDS model's disregard for essential material properties and tip geometry, while the disparities between MD simulation and experiment are primarily attributed to the inherent limitations in the simulated length scales and challenges in detecting initial subsurface cracks.

Application of high-strength, high-density, isotropic Si/C composites in commercial lithium-ion batteries

Although nanostructured Si can overcome the huge volume expansion during lithiation without breakage, in practical applications, it is Si/C composites that are used as anode in lithium batteries, in which volume expansion of Si can easily transmit to Si/C leading to rupture of composites, therefore, electrical contact loss and poor cyclability. So far, few reported Si/C composites can meet real application requirements. High structural strength of Si/C is a prerequisite for applications and, although it cannot inhibit the expansion when Si becomes Li15Si4, it can inhibit the irreversible expansion caused by the randomly increase of defect during the repeated phase transition of Si, and can prevent the rupture of composite particles during the compaction and cycling. In this work, a high-strength, high-density, isotropic Si/C composite was applied in commercial cylindrical cells with NCM811, and it exhibited a capacity retention of 83.8% over 1000 cycles at 2.5–4.2 V and 89.0% at 2.75–4.15 V, where charge/discharge rate was 0.5C/1C.

Liquid-Modulated Photothermal Phenomena in Porous Silicon Nanostructures Studied by μ-Raman Spectroscopy

In the present study, the effect of liquid filling of the nanopore network on thermal transport in porous Si layers was investigated by μ-Raman spectroscopy. The values of thermal conductivity of porous Si and porous Si-hexadecane composites were estimated by fitting the experimentally measured photoinduced temperature rise with finite element method simulations. As a result, filling the pores with hexadecane led to (i) an increase in the thermal conductivity of the porous Si-hexadecane composite in a wide range of porosity levels (40-80%) and (ii) a suppression of the characteristic laser-induced phase transition of Si from cubic to hexagonal form.

Kinetic studies of structure-H hydrate using a Langmuir adsorption model: Effects of methyl cyclohexane and methyl cyclopentane as large-molecule guest substances on methane hydrate

The present study investigates the kinetics of structure-H hydrate formation in the presence of large molecule guest substances (LMGS), Methyl cyclohexane (MCH) and Methyl cyclopentane (MCP), as well as methane as a help gas. The experiments were done at the temperatures range of 274.1–277.1 K. For studying the effect of LMGS on the kinetics of the hydrate formation, the initial pressure of each experiment was considered to be higher than the equilibrium pressure of structure-I methane hydrate formation. The molar consumptions of the help gas and guest substances during hydrate formation were calculated by using an algorithm based on the Langmuir adsorption theory. It was found that first step of a two-step process of hydrate formation in the presence of MCH and MCP is more related to the structure-I methane hydrate formation, so that the transition of sI to sH occurs after that. The results showed that the molar consumption of methane in the presence of MCH is more than that of MCP, and more structure-H hydrate is formed at all operational conditions. MCH could lower the gas/water interfacial tension dramatically and also affect the rate of sI hydrate formation. However, the MCP is more effective LMGS on the rate of sH hydrate formation as having the higher equilibrium pressures at all conditions. Finally, the consumption of help gas depends on the consumption of LMGS that it causes a constant participation ratio.

Effects of plasma screening on radiative transition and photoionization of Si[formula omitted]–Si[formula omitted] in a dense plasma environment

The screening induced by a dense plasma environment is crucially important for determining radiative atomic data including bound–bound radiative decay rates and photoionization cross sections, which are vital for obtaining accurate opacity. Previous experimental investigations of ionization potential depression have shown that the widely used analytical models of screening struggle to capture the essential physics in the solid-density plasma. In the present work, we investigate how plasma screening affects the radiative atomic data of Si10+–Si13+ embedded in a dense plasma environment using a self-consistent field finite temperature ion sphere model. The single-electron effective potential of an embedded atom has a short-range feature that determines the available number of bound states. Plasma screening is effective in modifying the matrix elements of the radiative dipole transitions, thereby generally increasing the photoionization cross section near the ionization threshold and decreasing the bound–bound radiative decay rates. The enhancement of the photoionization processes stems from lowering the ionization threshold and the shape and virtual-state resonances, where the upper bound levels become delocalized after a certain critical screening strength. With increasing plasma density, the Rydberg series for the bound–bound radiative transitions disappear successively.

Amorphous-to-Nanocrystalline Transition in Silicon Thin Films by Hydrogen Diluted Silane Using PE-CVD Method

Objective: Herein, we report the effect of variation of hydrogen flow rate on the properties of Si:H films synthesized using PE-CVD method. Raman spectroscopy analysis show an increase in crystalline volume fraction and crystallite size implying that hydrogen flow in PE-CVD promotes the growth of crystallinity in nc-Si:H films with an expense of a reduction in deposition rate. Methods: FTIR spectroscopy analysis indicates that hydrogen content in the film increases with an increase in hydrogen flow rate and hydrogen is predominantly incorporated in Si-H2 and (Si-H2)n bonding configuration. The optical band gap determined using E04 method and Tauc method (ETauc) show an increasing trend with an increase in hydrogen flow rate and E04 is found higher than ETauc over the entire range of hydrogen flow rate studied. Results and Conclusion: We found that the defect density and Urbach energy increases with an increase in hydrogen flow rate. Photosensitivity (σPhoto /σDark) decreases from ~103 to ~1 when hydrogen flow rate is increased from 30 sccm to 100 sccm and can be attributed to amorphous-to-nanocrystallization transition in Si:H films. The results obtained from the present study demonstrated that hydrogen flow rate is an important deposition parameter in PECVD to synthesize nc-Si:H films.

Critical behavior of the insulator-to-metal transition in Te-hyperdoped Si

Hyperdoping Si with chalcogens is a topic of great interest due to the strong sub-band-gap absorption exhibited by the resulting material, which can be exploited to develop broadband room-temperature infrared photodetectors using fully Si-compatible technology. Here, we report on the critical behavior of the impurity-driven insulator-to-metal transition in Te-hyperdoped Si layers fabricated via ion implantation followed by nanosecond pulsed-laser melting. Electrical transport measurements reveal an insulator-to-metal transition, which is also confirmed and understood by density functional theory calculations. We demonstrate that the metallic phase is governed by a power-law dependence of the conductivity at temperatures below 25 K, whereas the conductivity in the insulating phase is well described by a variable-range hopping mechanism with a Coulomb gap at temperatures in the range of 2--50 K. These results show that the electron wave function in the vicinity of the transition is strongly affected by the disorder and the electron-electron interaction.

High-performance boron-doped silicon micron-rod anode fabricated using a mass-producible lithography method for a lithium ion battery

Although silicon (Si) attracts great attention as a high-capacity anode material in lithium ion batteries (LiBs), a large volume being expanded during charge/discharge (de/lithiation) cycling is a significant problem resulting in a fast capacity fade. To prevent the problem, a variety of Si structures with nano/microscales have been incorporated into the anode, but such structures still have difficulties in terms of mass production. Herein, we present a new way to repetitively produce micron boron (B)-doped Si rods from Si wafer through laser interference lithography (LIL) in combination with the metal assisted chemical etching (MACE) process, enabling the mass-production of multiple Si rods at low cost. Moreover, the effects of the B-doping level of the produced Si rods on the electrochemical LiB performances are studied in detail. As a result, the lightly B-doped Si rod (~1015 atoms cm−3) anodes exhibit the highest initial capacity of 3524 mAh g−1 and cyclic performance, showing a high average Coulombic efficiency (CE) of 98.1% and a capacity fading rate (per cycle) of 0.11% during 500 cycles. It is due to the highest kinetics of de/lithiation on the surface of the lightly B-doped Si rod attributed to favorable phase transition of Si and diffusion of Li ions.

A Free Volume-Based Viscoplastic Model for Amorphous Silicon Electrode of Lithium-Ion Battery

The phase transition of Si from crystalline phase to amorphous phase with the formation of metastable amorphous structures of Li12Si7, Li7Si3, Li13Si4 and Li22Si5 after the first few cycles suggests that the Si in Si-based lithium-ion battery is mainly present in amorphous phase. In this work, we extend the free volume theory, which has been widely used in the deformation analysis of bulk metallic glass, to describe the cycling-induced visco-plastic deformation in amorphous Si-electrode during electrochemical cycling and establish a constitutive relationship with the flow unit of free volume for the plastic flow in lithiated Si. The plastic flow in lithiated Si is accompanied with the creation and annihilation of free volume. Using the constitutive relationship and incorporating the concentration-dependent mechanical properties of lithiated Si, we study the cycling-induced evolution of Cauchy stress and free volume in amorphous, thin-film Si-electrodes. The numerical results are in good accord with the experimental results reported in literature, which validates the approximation used in the analysis of the cycling-induced deformation of the amorphous, thin-film Si-electrodes.

In Situ Nano-thermomechanical Experiment Reveals Brittle to Ductile Transition in Silicon Nanowires.

Silicon (Si) nanostructures are widely used in microelectronics and nanotechnology. Brittle to ductile transition in nanoscale Si is of great scientific and technological interest but this phenomenon and its underlying mechanism remain elusive. By conducting in situ temperature-controlled nanomechanical testing inside a transmission electron microscope (TEM), here we show that the crystalline Si nanowires under tension are brittle at room temperature but exhibit ductile behavior with dislocation-mediated plasticity at elevated temperatures. We find that reducing the nanowire diameter promotes the dislocation-mediated responses, as shown by 78 Si nanowires tested between room temperature and 600 K. In situ high-resolution TEM imaging and atomistic reaction pathway modeling reveal that the unconventional 1/2⟨110⟩{001} dislocations become highly active with increasing temperature and thus play a critical role in the formation of deformation bands, leading to transition from brittle fracture to dislocation-mediated failure in Si nanowires at elevated temperatures. This study provides quantitative characterization and mechanistic insight for the brittle to ductile transition in Si nanostructures.

Evaluation of Mechanical and Tribological Properties of Directionally Solidified Al-Si Based FG Composite

The present work aims to fabricate graphite reinforced Aluminum-Silicon (Al-Si) based functionally graded composite (FGC). The FGC’s are obtained with the novel directional solidification technique under the influence of lateral vibrations. The accomplished cast composites are investigated for mechanical and tribological properties to understand the significance of vibrations. To validate the gradation in the structure, the FGC’s have been analyzed for hardness at the top and bottom portion. Results revealed that top portion exhibited high hardness with 66 BHN compared to the bottom portion with 48 BHN respectively. These observations were also supported by the scanning electron microscope (SEM) morphologies which revealed that concentration of Si was more at the top portion. The spatial transition of Si can be attributed to the presence of the chill at the bottom and to the influence of lateral vibrations which has led to variation of properties within the structure. Ultimate tensile strength (UTS) results also showed shift in the properties with the bottom portion exhibiting 143.23 MPa compared to the top portion with 98.3 MPa. Furthermore, wear analysis carried out at the top and the bottom portion of the FGC showed that there is a decrease in wear loss, coefficient of friction and specific wear rate at the top portion compared to the bottom portion. Worn-out surface analysis revealed that graphite addition had imparted the self-lubricating property at the top portion which could serve as anti-friction and anti-wear applications in the automotive sector

A novel ultra-high-temperature oxidation protective MoSi2-TaSi2 ceramic coating for tantalum substrate

To protect refractory metal against oxidation at ultra-high temperatures, a MoSi2-TaSi2 ceramic coating was prepared on a pure tantalum (Ta) substrate using a novel three-step process, which included dip-coating with a molybdenum slurry, vacuum sintering, and halide-activated pack cementation (HAPC). The original coating had a MoSi2-TaSi2 double-layer structure from the surface to the substrate. After oxidation at 1700°C for 8 h in air, the coating exhibited a complex multi-layer structure composed of SiO2-Mo5Si3-MoSi2-(Mo,Ta)5Si3-TaSi2-Ta5Si3 from the outer layer to the inner layer, due to the high-temperature phase transition and diffusion of Si and O. The coating effectively protected the Ta substrate at 1700°C for 12 h without failure, thereby demonstrating great improvement to its service life in an ultra-high-temperature aerobic environment. The protective effect was attributed to the integrity of the ceramic coating and the formation of a dense, uniform SiO2 film that effectively lowered the inward oxygen diffusion rate.

Effect of Eu on the silicon phase in Al-40Zn-5Si alloys

A series of Al-40Zn-5Si alloys with different additions of Eu were prepared by permanent mold casting. The nucleation phenomenon incorporating the modification of silicon phase was investigated by using the synchrotron radiation imaging technology, scanning electron microscopy, electron probe microanalysis and high resolution high-angle annular dark-field scanning transmission electron microscopy. It was found that the primary phase was α-Al dendrites and the pre-eutectic Si particles were precipitated continuously at the front of the solid/liquid interface in Al-40Zn-5Si alloys. The nodular pre-eutectic Si particles were observed when the Eu addition was 0.3%. Meanwhile, a flake-to-fibrous transition of eutectic Si was also observed. The needle-like eutectic Si crystals were seen to shoot out from the vicinity of primary α-Al dendrites into melt with high velocities leading the irregular eutectic interface in the unmodified Al-40Zn-5Si alloy. However, the eutectic grains with smooth interfaces nucleated mainly near primary or secondary α-Al branches in 0.3% Eu-modified Al-40Zn-5Si alloy. The eutectic grains began to nucleate on the nodular pre-eutectic Si particles when the α-Al surface reached so close to them. The formation of nodular pre-eutectic Si particles was attributed to the adsorption of Eu atoms along the <112> growth direction of Si and at the intersection of Si twins. This is fully consistent with the well-known poisoning of twin plane re-entrant edge (TPRE) and the impurity induced twinning (IIT) modification mechanisms proposed for interpreting the modification of eutectic Si.

Quantifying Contributions to Reversible and Irreversible Capacities of Silicon Electrodes

Silicon has received much attention as a next-generation anode material for lithium-ion battery (LIB) because it can give a theoretical capacity of up to 4000 mAh/g. Typically, silicon electrodes show poor cycle performance, which is attributed to large volume expansion during lithiation, pulverization of the active material, continuous solid electrolyte interphase (SEI) layer growth etc. Though, there are hardly any studies that can tell how much of the measured capacity comes from each process. The aim of this study is to establish a method to understand and quantify the contributions to the reversible and irreversible capacities of silicon anode in order to develop strategies to improve the stability of the electrodes. Here, we report the use of an electrochemical approach – depth of discharge test – to separate the charge-discharge capacities of crystalline silicon electrodes into four contributions: (1) SEI formation and electrolyte decomposition, (2) lithium accommodation in carbon and binder, (3) lithiation and delithiation of the Si active material, and (4) capacity loss associated with particle cracking and detachment. Silicon electrodes using bulk silicon particles (Sigma Aldrich), acetylene black (AB) and carboxymethyl cellulose (CMC) binder were made with a ratio of 4:3:3, 6:2:2 and 8:1:1. The electrodes are assembled into 2032-type coin cells with Celgard separator and Li metal as the counter electrode. 1M LiPF6 in fluorinated ethylene carbonate (FEC) and diethyl carbonate (DEC) = 1:1 by volume is used as the electrolyte. For the depth of discharge test, multiple cells were made, and each of them is initially discharged to different cutoff capacity (250, 500, 1000, 1500, 2000, 2500, 3000 and 3500mAh/g) and charged back to 1V. Figure 1a shows a summary of the initial discharge-charge curves of different cells with a composition of Si:AB:CMC = 4:3:3. The respective first charge capacity vs. first discharge capacity is summarized in Figure 1b, which shows a linear behavior that is shifted from the origin. The slope of the line corresponds to the intrinsic first cycle efficiency of Si, which is about 90% and is independent on the degree of lithiation. This suggests that no matter how much lithium is initially inserted, 10% of them remains in the lattice and cannot be removed. This is attributed to partial irreversibility of the crystalline-to-amorphous transition of Si during lithiation, and is consistent with a core-shell model of lithiation during first discharge. The x-intercept of Figure 1b is non-zero, which corresponds to the irreversible capacity of the electrode. The x-intercept depends on the composition of the electrode (see inset of Figure 1b) – larger x-intercept for large amount of carbon and binder, which is due to irreversibility from these two components. Accounting for all of these, we estimate the capacity from SEI formation and electrolyte decomposition to be about 16 mAh/(g Si) for bulk Si (with BET = 1.6 m2/g). SEI formation is expected to depend on particle size and surface area. We verify this by performing the depth of discharge test with ballmilled Si (in Ar at 200rpm for 24 hours) with BET = 6.6 m2/g. The capacity due to SEI formation during 1st discharge is increased to about 68 mAh/(g Si), and scales with BET surface area. We estimate that the SEI formation in our system to be about 10 mAh per square metres of active material surface. This value would depend on the type of electrolyte used in the system. Mechanical issues and particle isolations are observed in fully discharged electrode when the amount of binder is less than 20%. This is represented in the bend in the depth of discharge curve for the CMC-811 electrode, as in Figure 1b. Our results suggest that there is a threshold to mechanical breakdown. In the case of the CMC-811, high reversibility is still obtained when the discharge capacity is below 2000 mAh/g. With larger discharge capacity, volume expansion is larger, leading to severe capacity fading. In subsequent cycles, cycle stability is governed by the coulombic efficiency (CE) of the electrode - the larger the coulombic efficiency, the better the stability. The irreversible capacity is not only due to continuous SEI formation, but also to Li trapping in the active material and mechanical breakdown of the electrode. CE can be increased by limiting capacity, reducing particle size, or changing to a stronger binder such as polyimide. Some of results can be found in our recent publication1. More results will be shown during the meeting. [1] P.-K. Lee, Y. Li, D. Y. W. Yu, J. Electrochem. Soc. 164, A6206 (2017). Figure 1

Study of pattern transition in nanopatterned Si(100) produced by impurity-assisted low-energy ion-beam erosion

In this work, formation of self-organized Si nanostructures induced by pure Fe incorporation during normal incidence low-energy (1keV) Ar $$^+$$ ion bombardment is presented. It has been observed that the incorporation of Fe affects the evolution of the surface topography. The addition of Fe generates pronounced nanopatterns, such as dots, ripples and combinations of dots and ripples. The orientation of the ripple wave vector of the patterns formed is found to be in a direction normal to the Fe flow. The nanoripples with wavelength of the order of 39 nm produced is expected to be the lowest wavelength of the patterns reported on ion-beam-eroded structures under the incorporation of metallic impurities as per our knowledge. From the AFM and GISAXS analysis, it has been confirmed that the ripples formed are asymmetric in nature. The effect of the concentration of the Fe on morphological transition of the patterns has been studied using Rutherford backscattering measurements.

Interaction between phase transformations and dislocations at incipient plasticity of monocrystalline silicon under nanoindentation

Structural phase transformation and dislocation slip are two important deformation modes of monocrystalline silicon. In the present work, we elucidate mechanisms of inhomogeneous elastic-plastic transition in spherical nanoindentation of monocrystalline silicon by means of molecular dynamics simulations. The Stillinger-Weber potential is utilized to present simultaneous phase transformations and dislocation activities in the silicon nanoindentation. And a bond angle analysis-based method is proposed to quantitatively clarify silicon phases. The influence of crystallographic orientation on the silicon nanoindentation is further addressed. Our simulation results indicate that prior to the “Pop-In” event, Si(010) undergoes inelastic deformation accompanied by the phase transformation from the Si-I to the Si-III/Si-XII, which is not occurred in Si(110) and Si(111). While the phase transformation from the Si-I to the bct-5 is the dominant mechanism of incipient plasticity for each crystallographic orientation, dislocation nucleation is also an operating deformation mode in the elastic-plastic transition of Si(010). Furthermore, interactions between phase transformations and dislocations are more pronounced in Si(010) than the other two crystallographic orientations.

Insights from Studying the Origins of Reversible and Irreversible Capacities on Silicon Electrodes

Silicon electrodes can give high capacity as anodes for lithium-ion batteries. However, there has not been much work quantifying the different contributions to the reversible and irreversible capacities. Here, we report the use of an electrochemical approach – depth of discharge test – to separate the charge-discharge capacities of crystalline silicon electrodes into four contributions: (1) SEI formation, (2) lithium accommodation in carbon and binder, (3) lithiation and delithiation of the Si active material, and (4) capacity loss associated with particle cracking and isolation. We find that the intrinsic coulombic efficiency for the crystalline-to-amorphous transition of Si during initial cycle is about 90%, which is independent of particle size. SEI formation is estimated to be about 10 mAh per square meters of active material surface and scales with BET surface area. Mechanical issues and particle isolation are observed in fully discharged electrode when the amount of binder is less than 20%. Capacity limitation prolongs lifetime of Si electrode, but the overall performance is governed by the coulombic efficiency (CE) during cycle. Low CE is due to continual SEI formation with cycling, increase utilization of Si upon cycling, trapping of Li in the material and mechanical failure of the electrode.

Crystallization kinetics in Si-1 at%Sn during rapid solidification in undercooled melt

In order to elucidate the cause of the morphological transition of crystals growing in an undercooled melt of semiconducting materials, we carried out the containerless solidification of undoped Si and Si-1at%Sn using a CO2 laser-equipped electromagnetic levitator (EML). The crystallization of these materials was successfully achieved under controlled undercooling. The relation between the shape of growing crystals and the degree of undercooling in Si-1at%Sn was similar to that in undoped Si; that is, plate-like needle crystals were observed at low undercooling, whereas at medium and high undercooling the shape of growing crystals changed to massive dendrites. The grain-size of as-solidified samples of Si-1at%Sn was remarkably small compared with that of undoped Si. The surface morphologies of samples solidified by dropping the melt onto a chill plate of mirror-polished silicon consisted of typical twin-related <110> dendrites. On the other hand, samples that were dropped from the undercooled state consisted of twin-free <100> dendrites. The nucleation rate of two-dimensional nuclei calculated on the basis of two mechanisms, which are the twin-plane re-entrant edge mechanism and the twin-free mechanism, suggested that the morphological transition to twin-free <100> dendrites from twin-related <110> dendrites occurs when the degree of undercooling becomes larger than the critical value. These results indicate that the cause of the morphological transition of Si growing in the undercooled melt is not the roughening transition of the crystal–melt interface but the transition of the nucleation kinetics to the twin-free mechanism from the twin-related mechanism.

Core-level attosecond transient absorption spectroscopy of laser-dressed solid films of Si and Zr

We investigated experimentally as well as theoretically the ultrafast response of the wave function of the conduction band (CB) of Si and Zr to a near-infrared laser field using extreme ultraviolet (XUV) absorption spectroscopy in the spectral range of 80--220 eV. The measured dynamics of the XUV transmission demonstrates that the wave function of the CB follows the electric field of the dressing laser pulse. In these terms, laser dressing was earlier mainly studied on gases. Measurements with two-femtosecond and 200-attosecond temporal steps were performed in the vicinity of the $\mathrm{Si}\phantom{\rule{0.16em}{0ex}}{L}_{2,3}$ edge near 100 eV, the $\mathrm{Si}\phantom{\rule{0.16em}{0ex}}{L}_{1}$ edge near 150 eV, and the $\mathrm{Zr}\phantom{\rule{0.16em}{0ex}}{M}_{4,5}$ edge near 180 eV. The observed changes were dependent on the core states being excited by the XUV probe pulse. At the $2p$ to CB transitions of Si, the XUV transmission increased via the effect of the dressing laser pulse, while at the $2s$ to CB transition of Si and the $3d$ to CB transition of Zr, the XUV transmission decreased. Furthermore, beats between the transition from $2{p}_{1/2}$ and $2{p}_{3/2}$ levels of Si and from $3{d}_{3/2}$ and $3{d}_{5/2}$ levels of Zr were observed with 20.7 fs and 3.6 fs periods.

Crystal to Amorphous Transition of Si and Ar Implanted Silicon Using Single-Effective Oscillator Model

Crystal to Amorphous Transition of Si and Ar Implanted Silicon Using Single-Effective Oscillator Model