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This investigation showcases the viability of producing SixGe1−x bulk single crystals via the Czochralski technique. A high Si content in Ge-rich SiGe wafers is highly desirable for various applications in quantum technology, particularly as strain-relaxed buffers for the realization of hole spin qubits in strained Ge quantum well heterostructures. The focus lies on the bulk crystal growth of such materials and their chemical and structural quality. For this, the Czochralski process, starting from a highly pure Ge seed and melt, utilizing continuous feeding by dissolution of Si rods was performed.Si0.16Ge0.86 wafers with a diameter of up to 15 mm obtained from the bulk crystal exhibited homogeneous structural quality in contrast to the conventionally used epitaxial strain-relaxed SiGe buffers. The compositional fluctuations of Si measured throughout the wafer were below 0.4 at. % in addition to a dislocation density below 3 × 106 dislocations/cm2. Interestingly, the central region of the wafer displayed no measurable compositional fluctuations and contained less than 105 dislocations/cm2. Furthermore, the difficulties and limits of growing such SiGe crystals are discussed, such as the continuous dissolution of Si during growth and the formation of oxides in the melt during growth. The current observations indicate significant potential for further enhancement of the crystal quality and to realize higher Si concentrations using the Czochralski technique. [ABSTRACT FROM AUTHOR]

With more than thirty years of research and development until commercialization, performance, reliability, and robustness of silicon carbide (SiC) based devices have been improved significantly due to drastic reduction in crystal defects from the well-controlled processes of crystal growth and device fabrication. It is crucial to investigate the effects of SiC crystal defects on the electrical characteristics of devices. Here, an up-to-date development of the correlation between crystal defects of SiC with electrical performance of the devices has been reviewed. The effect of defects on the electrical parameters of the device and the failure mechanism are discussed, and the development of SiC in recent years is prospected. [ABSTRACT FROM AUTHOR]

In this paper, we demonstrate a novel strategy to introduce Fe into a Bi 2 Se 3 system through growth of crystals with nominal composition (FeSe) x Bi 2 Se 3. For x < 0.04 , Fe is shown to act mostly as a non-magnetic impurity; it uniformly enters the lattice and monotonically increases the c -lattice parameter, electronic doping level, and Shubnikov–de Haas mobility. The most striking observation is the record high Hall mobility of 8600 cm 2 /V s at 4.2 K for the smallest FeSe content (x = 0.002) that further decreases with x. Elevated mobility is accompanied by a high residual resistance ratio and a rather moderate shift of Shubnikov–de Haas oscillations to a smaller field. These findings indicate that Fe admixture cures the point defects in Bi 2 Se 3 and, thus, opens an effective way to suppress the defect subsystem in Bi 2 Se 3 -based topological insulator materials. [ABSTRACT FROM AUTHOR]

The pressure dependence of the R1 and R2 peaks of the fluorescence spectra of high-pressure-synthesized corundum-type Ga2O3:Cr3+ was measured up to 50 GPa using a diamond anvil cell pressurized at room temperature in an argon medium. The temperature dependence of the R1 and R2 peaks was measured at low temperatures under ambient pressure from 303 to 83 K. From the measurement results, the pressure scale and low-temperature scale were determined using R1 and R2. X-ray diffraction experiments at high pressure, which were performed to confirm the effective range of the pressure scale, showed that the corundum structure undergoes a phase transition to a Rh2O3(II)-type structure at 54–65 GPa; this pressure scale is, thus, valid up to approximately 50 GPa. We also investigated the crystal growth time to optimize the crystal size of Ga2O3:Cr3+ for diamond anvil cell experiments. [ABSTRACT FROM AUTHOR]

The overall physical properties of polycrystalline materials vary depending on the microscopic individual grain boundary (GB) properties and their structures. Unlike previous studies that only examined the structure and properties of a specific GB, this study focuses on understanding the thermal boundary conductance (TBC) through artificial and systematic changes in the GB structures. This is achieved by combining an advanced technique to map local thermal expansion displacement using the laser heterodyne photothermal displacement method and a unique crystal growth method that induces spontaneous changes in the GB structures. As a result, we could quantify the TBC of the GB in silicon, considering the changes in three structural parameters of GB: azimuthal misorientation (α), asymmetry angle (β), and deviation angle (θ) from the growth direction. Our findings reveal that the TBC increases with increasing θ, whereas parameters α and β have negligible effects. The underlying physics of this relationship is discussed in terms of local carrier concentration and impurity segregation. These results demonstrate the crucial role of the GB structures in influencing the local TBC, shedding light on potential avenues for enhancing the macroscopic properties of polycrystalline materials by engineering GBs. [ABSTRACT FROM AUTHOR]

This report (I) aims to investigate defect behavior during the growth of heavily phosphorus (P)-doped Czochralski silicon (HP-Cz-Si) crystals. The defects and P chemical states in as-grown crystals with a resistivity of 0.6 mΩ cm and the wafers annealed at around 600 °C were evaluated by transmission electron microscopy and hard x-ray electron spectroscopy (HAXPES). Micro-dislocation loops (MDLs) were observed in the bottom portion of the crystal, and larger stacking faults (SFs), including complex dislocation clusters, were observed in the middle portion. HAXPES revealed two different P states, P1 and P2. P1 was attributed to a substitutional P (Ps). The P2 present in as-grown crystals was found to be electrically active, while the newly formed P2 after annealing was electrically inactive, indicating that they are in different states. HAXPES evaluation of HP-Cz-Si after electron irradiation showed similar behavior to P2 after annealing, suggesting that P-vacancy (V) clusters are formed when the crystals are held at temperatures below 600 °C during crystal growth. Combining the experimental results with our theoretical analysis in the report (II) based on density functional theory calculations, we identified the following defect formation mechanisms. Interstitial P (Pi) atoms introduced at the melting point become supersaturated during cooling to 600 °C, and MDLs are generated by the aggregation of Si self-interstitials (Is) released through a position exchange from Pi to Ps. In crystal portions with a long residence time below 600 °C, supersaturated Ps transforms into P–V clusters, and Is generated simultaneously are absorbed by the MDLs, which grow into SFs containing dislocation clusters. [ABSTRACT FROM AUTHOR]

Recent studies including our own report (I) have revealed that heavily phosphorus (P) doped Czochralski-silicon (HP-Cz-Si) exhibits peculiar defect behaviors during crystal growth. HP-Cz-Si crystals with a low resistivity of around 0.6 mΩ cm (P concentration of 1.3 × 1020 P cm−3) have interstitial-type stacking faults (SFs) and dislocations, which degrade device characteristics. The purpose of this paper is to clarify what causes the defect behavior in HP-Cz-Si through theoretical calculations. The thermal equilibrium concentrations of substitutional P (Ps), interstitial P (Pi), and (Ps)n-vacancy (V) clusters (n = 1−4) were determined by using density functional theory (DFT) calculations. The concentrations of Pi ([Pi]) and (Ps)nV ([(Ps)nV]) balanced with the given Ps concentration ([Ps]) were obtained as a function of the total P concentration ([P]) and the temperature. On the basis of the calculated results those can quantitatively explain our experimental results in the report (I), we propose a defect model that accurately represents HP-Cz-Si crystal growth. The main feature of the model is that the incorporated Pi atoms at the solid/liquid interface around [Pi] = 1017 Pi cm−3 cause the formation of SFs and dislocations during the HP-Cz-Si crystal growth with around [P] = 1020 P cm−3. Furthermore, DFT calculations were performed for Pi segregation on the SF and for the photoelectron spectra of P 1s measured by hard x-ray photoelectron spectroscopy to explain the other experimental results in the report (I). [ABSTRACT FROM AUTHOR]

III-nitrides have fomented a revolution in the lighting industry and are poised to make a huge impact in the field of power electronics. In the III-nitride family, the crystal growth and use of hexagonal BN (h-BN) as an ultrawide bandgap (UWBG) semiconductor are much less developed. Bulk crystals of h-BN produced by the high-temperature/high-pressure and the metal flux solution methods possess very high crystalline and optical qualities but are impractical to serve as substrates or for device implementation as their sizes are typically in millimeters. The development of crystal growth technologies for producing thick epitaxial films (or quasi-bulk or semi-bulk crystals) in large wafer sizes with high crystalline quality is a prerequisite for utilizing h-BN as an UWBG electronic material. Compared to traditional III-nitrides, BN has another unique application as solid-state neutron detectors, which however, also require the development of quasi-bulk crystals to provide high detection efficiencies because the theoretical efficiency (ηi) relates to the detector thickness (d) by η i = 1 − e − d λ , where λ denotes the thermal neutron absorption length which is 47 μm (237 μm) for 10B-enriched (natural) h-BN. We provide an overview and recent progress toward the development of h-BN quasi-bulk crystals via hydride vapor phase epitaxy (HVPE) growth and the attainment of thermal neutron detectors based on 100 μm thick 10B-enriched h-BN with a record efficiency of 60%. The thermal neutron detection efficiency was shown to enhance at elevated temperatures. Benchmarking the crystalline and optical qualities of h-BN quasi-bulk crystals with the state-of-the-art mm-sized bulk crystal flakes and 0.5 μm thick epitaxial films identified that reducing the density of native defects such as vacancies remains the most critical task for h-BN quasi-bulk crystal growth by HVPE. [ABSTRACT FROM AUTHOR]

Two-dimensional colloidal crystals assembled from polystyrene nanospheres have emerged as a pivotal foundation for fabricating large-area nano-functional surfaces. These assemblies, defined by their hexagonal close-packed configuration and interlaced with grain boundaries, have garnered significant attention for applications in plasmonic structures, catalysts, photonic crystals, and inverse opals. Nonetheless, achieving consistent large-scale regularity has proven challenging due to unpredictable crystal growth and the introduction of defects. Utilizing acoustic waves excited from the airside, our experiments demonstrate the significant effects of such waves on the self-assembly process, leading to larger crystal domains and reduced defects. In comparison to the extensively studied water-end excitation techniques, our air-end excitation method introduces a novel dynamic in regulating colloidal monolayer crystallization and presents a comprehensive analysis of varying acoustic parameters, frequency, amplitude, and waveform. These findings reveal the potential of airside acoustic annealing in refining the structure of two-dimensional colloidal arrays. To elucidate our experimental observations, we delve into the theoretical underpinnings of particle dynamics, driven by classical hydromechanical constraints like surface tension and gravity. Using a qualitative estimate, we shed light on the resonant excitations and their potential role in optimizing the self-assembly process, especially focusing on resonances pertinent for enhancing cluster enlargements. Conclusively, our research, steeped in robust theoretical frameworks and groundbreaking experimental techniques, offers a multifaceted solution for perfecting two-dimensional colloidal arrays. This combined approach not only broadens the scope of acoustically induced crystallization but also charts a path for its adoption across diverse environments, signaling transformative prospects for nanomanufacturing and optical research. [ABSTRACT FROM AUTHOR]

Crystal growth is a complex process with far-reaching implications for high-performance materials across various fields. Recent advancements in structural analysis methods such as polyhedral template matching, which allows semiconductor-specific analysis, coupled with simulation technology, have enabled the comprehensive study of crystallization dynamics in semiconductors. However, the exploration of polycrystalline semiconductors created with minimal external intervention of the crystallization processes is relatively uncharted in comparison with metals. In this study, we employ molecular dynamics to simulate the growth of polycrystalline CdTe/CdS with the assumptions of classical mechanics, a Stillinger–Weber potential, an amorphous substrate, and common vapor growth conditions to allow the polycrystalline structures to evolve naturally. Post-simulation, we identify and analyze impactful structures and events, comparing them to theory and experiment to gain insight into various modes of crystallization dynamics. Two research questions guided the study: (1) How realistic are assumption-less simulated polycrystalline semiconductor structures? (2) To what extent can the approach provide insight into crystallization? The simulations, performed with minimal external control, yield polycrystalline structures mirroring experimental findings. The analysis reveals key crystallization insights, such as the role of amorphous atoms in the transition from nucleation to grain growth and the transformative impact of single events, such as dislocations, on crystallization dynamics. The method paves the way for reproducing and analyzing realistic polycrystalline semiconductor structures with minimal simulation assumptions across various growth modes. [ABSTRACT FROM AUTHOR]

This study is concerned with a theory of two-step nucleation and growth of crystals in a metastable liquid. This mechanism is that crystalline nuclei formation occurs in dense liquid clusters suspended in the solution. These clusters contain higher solution concentration and viscosity, leading to a lower surface free energy barrier and faster phase transition route. The theory is based on growth laws of crystals during the two-step bulk phase transformation. At the initial stage, the crystals evolve in a diffusion-limited environment with almost unchanged supersaturation. At the second stage, they become larger, move beyond these clusters, and evolve in accordance with a hyperbolic tangent law. A generalized particle growth law joining the first and second stages is obtained by stitching the diffusion limited and hyperbolic tangent laws. On this basis, an integrodifferential model of the evolution of a polydisperse ensemble of crystals was formulated and solved. The crystal-size distribution function increases and the solution supersaturation remains practically unchanged until the particle size corresponds to a transition in the particle growth rate from a diffusion-limited branch to a hyperbolic tangent branch. This is followed by an increase in the crystal growth rate, a decrease in the distribution function and solution supersaturation. Then the distribution function increases up to the maximum size of crystals grown in the solution. A sufficiently long time interval of almost constant supersaturation and the N-shaped behavior of the distribution function are the consequences of a two-step nucleation and growth mechanisms. [ABSTRACT FROM AUTHOR]

Optically active spin defects in semiconductors can serve as spin-to-photon interfaces, key components in quantum technologies. Silicon carbide (SiC) is a promising host of spin defects thanks to its wide bandgap and well-established crystal growth and device technologies. In this study, we investigated the oxygen-vacancy complexes as potential spin defects in SiC by means of ab initio calculations. We found that the OCVSi defect has a substantially low formation energy compared with its counterpart, OSiVC, regardless of the Fermi level position. The OCVSi defect is stable in its neutral charge state with a high-spin ground state (S = 1) within a wide energy range near the midgap energy. The zero-phonon line (ZPL) of the OCVSi0 defect lies in the near-infrared regime, 1.11–1.24 eV (1004–1117 nm). The radiative lifetime for the ZPL transition of the defect in kk configuration is fairly short (12.5 ns). Furthermore, the estimated Debye–Waller factor for the optical transition is 13.4%, indicating a large weight of ZPL in the photoluminescence spectrum. All together, we conclude that the OCVSi0 defect possesses desirable spin and optical properties and thus is potentially attractive as a quantum bit. [ABSTRACT FROM AUTHOR]

Experimental and simulation studies were conducted for surface segregation-limited kinetics of nitrogen incorporation into a 4H-SiC crystal during physical vapor transport (PVT) crystal growth. It was revealed that the nitrogen incorporation is kinetically limited by the step-flow velocity on the growing crystal surface of a 4H-SiC crystal; in this study, the surface step-flow velocity at the growth front was deduced from the local inclination angle of the growth front measured from the (000 1 ¯) plane, assuming a uniform growth rate along the c-axis (crystal growth direction) across the growth front, and the nitrogen concentration across the growth front was measured using Raman scattering microscopy. The step-flow velocity dependence of nitrogen incorporation was theoretically analyzed using a two-site-exchange model, and the simulated dependence using the model was in good agreement with the experimental data. On the basis of these experimental and simulation results, kinematical and energetical aspects of nitrogen incorporation at the growth front of a 4H-SiC crystal during PVT growth are discussed. [ABSTRACT FROM AUTHOR]

Metallic glasses have the potential to become transformative materials, but this is hindered by the lack of ability to accurately predict which metallic alloys will form good glasses. Current approaches are limited to empirical rules that often rely on parameters that are unknown until the glasses are made, rendering them not predictive. In this Perspective, properties of metallic liquids at elevated temperatures and how these might lead to better predictions for glass formation are explored. A central topic is liquid fragility, which characterizes the different dynamics of the liquids. What fragility is and how it might be connected to the liquid structure is discussed. Since glass formation is ultimately limited by crystallization during cooling, recent advances in crystal growth and nucleation are also reviewed. Finally, some approaches for improving glass stability and glass rejuvenation for improved plasticity are discussed. Building on a summary of results, some key questions are raised and a prospective for future studies is offered. [ABSTRACT FROM AUTHOR]

We investigated the minority carrier lifetime and behavior of lattice defects in ZnSnP2 bulk crystals through experiments on carrier recombination and defect properties. Advanced deep level transient spectroscopy (DLTS) revealed that an electron trap with a short time constant at 0.2 eV below the conduction band minimum edge may contribute to the short minority carrier lifetime evaluated by time-resolved photoluminescence (TRPL). The temperature dependence of steady-state photoluminescence suggested that the carrier recombination through the electron trap was nonradiative around room temperature, which supports the fact of the short carrier lifetime and lower current density in ZnSnP2 solar cells. Previously reported theoretical calculation suggests that such a trap comes from the antisite defect of Sn from the viewpoint of the thermodynamic transition level. We, thus, prepared ZnSnP2 crystals by the solution growth method under conditions with a higher chemical potential of Zn, and we achieved the enhancement of the carrier lifetime compared to that under other growth conditions. In this case, the evaluation of the liquidus temperature and chemical potentials by a thermodynamic model indicated that the formation of Sn antisite was effectively suppressed by a lower precipitation temperature in addition to the effect of chemical potentials. Finally, we demonstrated the improvement of current density in ZnSnP2 solar cells using crystals with a longer lifetime, especially in the longer wavelength range. [ABSTRACT FROM AUTHOR]

We investigated the minority carrier lifetime and behavior of lattice defects in ZnSnP2 bulk crystals through experiments on carrier recombination and defect properties. Advanced deep level transient spectroscopy (DLTS) revealed that an electron trap with a short time constant at 0.2 eV below the conduction band minimum edge may contribute to the short minority carrier lifetime evaluated by time-resolved photoluminescence (TRPL). The temperature dependence of steady-state photoluminescence suggested that the carrier recombination through the electron trap was nonradiative around room temperature, which supports the fact of the short carrier lifetime and lower current density in ZnSnP2 solar cells. Previously reported theoretical calculation suggests that such a trap comes from the antisite defect of Sn from the viewpoint of the thermodynamic transition level. We, thus, prepared ZnSnP2 crystals by the solution growth method under conditions with a higher chemical potential of Zn, and we achieved the enhancement of the carrier lifetime compared to that under other growth conditions. In this case, the evaluation of the liquidus temperature and chemical potentials by a thermodynamic model indicated that the formation of Sn antisite was effectively suppressed by a lower precipitation temperature in addition to the effect of chemical potentials. Finally, we demonstrated the improvement of current density in ZnSnP2 solar cells using crystals with a longer lifetime, especially in the longer wavelength range. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulations are used to determine the properties of the crystal–liquid interfaces of Ni and Ni50Al50. The interfacial free energies and kinetic growth coefficients for different crystal orientations are estimated using simulations of crystal–liquid systems at the melting temperature T m from time- and wavenumber-dependent capillary wave height–height correlation functions. Growth coefficients are also determined from non-equilibrium simulations using the free solidification method, which compares well with those obtained from analysis of capillary wave fluctuations. Crystal growth in pure Ni is about a factor of 10 faster than in the binary Ni50Al50 system. The interfacial properties of the B2 intermetallic crystal phase of Ni50Al50 exhibit much lower anisotropy than those of the face-centered cubic crystalline structure of Ni. [ABSTRACT FROM AUTHOR]

Much effort has been expended to obtain thin films of metastable solid solutions of germanium (Ge) that contain as high tin (Sn) content as possible because of their excellent electronic and optoelectronic properties. On the basis of our previous study on amorphous Ge, we demonstrated in this study that irradiation of substrate-free films of amorphous Ge100−xSnx (x = 8, 11, and 19 at. %) with a low-energy electron beam of 3 keV at ambient temperature can induce instantaneous wide-area crystallization (explosive crystallization). Characteristic spiral crystal growth associated with explosive crystallization occurred with areas exceeding 50 μm in diameter around a scanned area of the electron beam of 8 × 8 μm2. As a result, solid solutions of GeSn with Sn concentration up to 19 at. % were obtained with the suppression of precipitation of β-Sn. The region of explosive crystallization reduced in size with increasing Sn content. In addition, thermal analyses revealed that the heat released during crystallization of amorphous GeSn films decreased with increasing Sn content. This relationship indicates that the heat release at the growth front plays a key role in the propagation of explosive crystallization of a-GeSn. [ABSTRACT FROM AUTHOR]

Sapphire has increasing demand toward optoelectrical devices like LED; its big challenge is to find reasonable growth mechanisms for high quality large size single crystals. In this paper, we proposed both theoretical and experimental studies to clarify multiscale behaviors within the Al2O3 growth system. Molecular dynamics simulation for sapphire crystal growth along c-, a-, and m-axes, and solid–liquid interface structure, and grown 2″ sapphire via the Czochralski method along the c-axis, were reported herein. Our studies show that α-Al2O3 growth behaviors along different crystal directions are different, which is different from the amorphous Al2O3 phase transition at the various α-Al2O3 planes. α-Al2O3 crystal growth in the c-axis system may be a complex process involving solid–liquid and solid–solid transformations, rather than a single solid–liquid transformation that happened in the systems growing along the a- and m-axes. Within the time scale of simulation, the crystals cannot be grown by the lattice period of the seed crystal along the c-axis and transform into γ-Al2O3 rather than α-Al2O3, while it is opposite along the a- and m-axes. This may be the microscopic reason why it is difficult to grow sapphire along the c-axis in the experiment. An abrupt change in the interfacial structure is the key reason to inhibit the transformation of liquid Al2O3 into α-Al2O3 along the c-axis. [ABSTRACT FROM AUTHOR]

The ordering of a light-induced structure of isolated circular ferroelectric nanodomains was discovered in lithium tantalate crystals under multiple scanning by infrared laser irradiation. The effect was considered as domain arising and growth under the action of alternating in sign pyroelectric field arising during sample heating and subsequent cooling. The circular domains appeared due to 1D to 2D shape transformation after the second scan and grew during subsequent scanning by merging with arising domains accompanied by shape restoration. The ordering of the domain pattern during multiple scanning characterized by an increase in the peak of the autocorrelation function was attributed to domain interaction. This mechanism was confirmed by computer simulation using the kinetic approach based on the analogy between the growth of domains and crystals. It was demonstrated that the quasi-regular pattern of one-size circular domains could be created by scanning with shift. The discovered domain ordering effect is similar to that in magnetic materials. [ABSTRACT FROM AUTHOR]

Transition metal dichalcogenides, mainly focusing on MoS2, have attracted intensive studies in terms of their electronic and optical properties. Their lower-dimensional counterparts, such as nanoribbons and nanoclusters, gradually draw more research attention because of their potential applications in various electronic and spintronic devices. The edge states are essential to determine the intriguing electronic and magnetic properties of the nanocrystals. In this review, we mainly focus on the zigzag edges in the MoS2 system because they are more common in experiments. We first review the physical properties of the unreconstructed edges and then introduce the principles of edge reconstructions, the electron counting model (ECM). Then, based on the ECM, intrinsic edge reconstructions with different periodicities are discussed. The literature we reviewed suggests that the conductivities and magnetism of the edge states are highly related to the periodicities of the edges. Finally, the effects of the edge passivation with extrinsic atoms are reviewed. Edge passivation plays an important role in tuning the electronic and magnetic properties of the edge states and determining the morphology during the crystal growth. Furthermore, MoS2 zigzag edges could be an ideal platform to investigate the interplay between the edge states with different periodicities and magnetic dopants in the future. [ABSTRACT FROM AUTHOR]

The atomic crystallization behaviors at the crystal–melt interfaces in a broad range of undercoolings are investigated by molecular dynamics simulations for two representative pure metals, FCC Cu and BCC Ta. Results show that the atomic transformation displacements against temperature for both metals have the same trend, i.e., increasing significantly as temperature goes up at small undercooling and keeping invariant at large undercooling. By classifying the interfacial atomic attachment behaviors into ballistic and diffusive motions based on the displacement analysis, it is found that the crystal growth of both metals involves many ballistic attachments, and a small increment of diffusive attachments at the Ta interface leads to a significant energy barrier for crystallization comparing to that of Cu. The temperature effects on the interfacial structures and atomic dynamics to attach onto the crystal are also studied in detail, and their correlations with the different growth mechanisms at low and deep undercoolings are disclosed. Finally, the crystallization rate is proved to be dominated by the atomic transformation displacement and interfacial atomic movement rate for either metal, rather than the atomic thermal velocity or liquid diffusion coefficient. [ABSTRACT FROM AUTHOR]

Thermally stimulated current (TSC) spectroscopy was used to characterize electronic trap states in the perovskite CsPbCl3 bulk single crystals which are promising for gamma ray detection. The TSC spectra indicate the presence of multiple traps over the temperature range from 80 K to above room temperature. The possible analytical defects identified were VCs and VCl vacancies and Pbi interstitials that have concentrations of the order of 1011−1016 cm−3 and capture cross sections of ∼10−18 cm2. A comparison of crystals grown from different ingots reveals that the concentration of defects in the crystal with an improved growth procedure is about one to four orders of magnitude less than those of a crystal from an earlier growth process. A further reduction and elimination of trap states within the perovskite ingot should lead to crystals with improved mobilities, carrier lifetimes, and detector response characteristics. [ABSTRACT FROM AUTHOR]

Beta-gallium oxide (β-Ga2O3) has recently attracted significant attention as an outstanding candidate for ultra-wide bandgap applications due to its unique advantages. Point and extended defects in β-Ga2O3 can significantly reduce the net doping and play an essential role with their functionality in advancing β-Ga2O3 device performance. It is, therefore, critical to gain an atomic level understanding of the structure of the defects and how they correlate to important properties of defects in β-Ga2O3. In this Perspective, we provide an overview of the recent characterization works involving scanning transmission electron microscopy and related techniques revealing the detailed structure of various point and extended defects in β-Ga2O3 and β-(AlxGa1−x)2O3 heterostructures. This article aims to offer insight into how defects determine important aspects of the material, such as in crystal growth, dopant incorporation and activation, and phase stability. The new information that we summarize here is expected to help achieve atomic scale control of defects in β-Ga2O3 materials and devices for development of the next generation power electronics applications. [ABSTRACT FROM AUTHOR]

Predictions of ultrahigh thermal conductivity in boron arsenide using first-principles calculations have motivated research to synthesize crystals and investigate their properties. In 2018, three groups reported synthesizing small single crystals of boron arsenide that exhibit thermal conductivity of 700–1300 W m−1 K−1 at room temperature. The progress in crystal growth has attracted significant attention and has inspired additional theoretical and experimental research. This brief review provides an overview of recent theoretical and experimental studies on boron arsenide, mostly since 2018. Progress in theoretical calculations, synthesis methods, characterizations, physical properties, and potential applications are presented, followed by a discussion of the remaining challenges and outlook for boron arsenide research. [ABSTRACT FROM AUTHOR]

The present Tutorial provides a description of the growth of bulk β-Ga2O3 single crystals by the Czochralski method with a focus on the critical growth aspects. In particular, it details the thermodynamics of Ga2O3 as the key factor for crystal growth along with comprehensive solutions that are essential for crystal size scale-up. Also, free carrier absorption is discussed, as it has a great impact on growth stability. The crystal growth direction and intentional doping, as important factors for crystal growth, are described as well. All of the aspects of the crystal growth are accompanied by resulting crystals, their structural quality, and basic physical properties. [ABSTRACT FROM AUTHOR]

We demonstrate a pathway employing crystal polarity controlled asymmetric impurity incorporation in the wide bandgap nitride material system to enable 3D doping control during the crystal growth process. The pathway involves polarity specific supersaturation modulated growth of lateral polar structures of alternating Ga- and N-polar GaN domains. A STEM technique of integrated differential phase contrast is used to image the atomic structure of the different polar domains and their single atomic plane boundaries. As a demonstration, 1 μm wide alternating Ga- and N-polar GaN domains exhibiting charge balanced and periodic domains for superjunction technology were grown. The challenges in characterizing the resulting 3D doping profile were addressed with atom probe tomography with atomic scale compositional resolution corroborating capacitance measurements and secondary-ion mass spectroscopy analysis. [ABSTRACT FROM AUTHOR]

Granular molecular crystals show a large variation in the orientation, length, shape, and cohesive interactions of interfaces when embedded in a polymer matrix. But the determination of the associated excess of free energy is not straightforward, especially due to the entropic contribution which is not negligible for molecular compounds. The surface free energy (SFE) is also important to predict crystal shapes and growth or to prove crucial insights into the mesoscale interfaces in the granular composites often with interfacial defects, voids, and pores. In this paper, we use Molecular Dynamics (MD) and assess and adapt two non-equilibrium methods, namely, non-equilibrium thermodynamic integration (NETI) and modified steered MD (SMD), to determine the SFE of various facets of a high-energy molecular crystal of interest: β-HMX. Starting with defect-free surfaces, both methods agree well with experiment concerning the most stable facets, whose energy is further lowered by a large entropic contribution. For some facets, surface creation (debonding process) and annihilation (bonding process) show fundamentally different paths, henceforth irreversible. Then, we discuss some sources of discrepancy between theoretical and experimental SFE, considering non-reversible dissipative events, surface roughness, and differences between various experimental techniques. These non-equilibrium methods can be applied to a wide range of molecular crystals and to study interface stability in polycrystals or with binding polymers, including the effects of various defects. [ABSTRACT FROM AUTHOR]

Nano metallic materials are promising candidates in many engineering applications, whereas their thermal stability is generally of great concern. In this study, molecular dynamics simulations were performed to study the crystal growth process of CuZr nanorods with different diameters. An appreciable size effect was observed in the crystal growth rates. However, the trend of size dependence could be reversed by changing the temperature. For temperatures above 925 K, nanorods of smaller diameters grow slower than those with larger diameters, while for temperatures below 925 K, smaller nanorods grow faster. It turns out that the temperature dependent size effect originates from the competition between the thermodynamic and kinetic factors. Atoms in the surficial region of the nanorods have higher mobility while lower thermodynamic driving force for growth than those in the interior. Under different temperatures, the overwhelming factor varies, leading to the temperature dependent size effect. A phenomenological model was proposed accordingly to describe the size dependence, which is found to work well under all temperatures explored. [ABSTRACT FROM AUTHOR]

In this work, we present the impact of using Na2CO3 as a sintering aid and grain growth agent on the crystal structure, microstructure, and piezoelectric properties of (Bi0.5Na0.5)TiO3 ceramics. The addition of Na2CO3 leads to a substantial increase in the grain size and density even at a reduced sintering temperature of 1025 °C. However, at the same time, the value of the piezoelectric constant d33 drops dramatically. Using high-resolution x-ray diffraction analysis, we demonstrate that the decrease in piezoelectric constant is due to a change in the chemical composition of the (Bi0.5Na0.5)TiO3 base material rather than due to the change in the grain size. High Na2CO3-addition levels lead to the formation of Bi2O3 as a secondary phase during sintering too. [ABSTRACT FROM AUTHOR]

Forward domain growth representing one of the main stages of domain switching is studied for isolated domains and domain arrays appearing as a result of tip-induced switching on the non-polar cuts of lithium niobate crystals. Formation of the wedge-like domains with a high aspect ratio and charged domain walls is observed. The domain growth in the area with a negligible external field is considered in terms of the kinetic approach based on analogy with crystal growth. The domain wall motion by step generation and propagation of the charged kinks is discussed. It is proposed that the switching field contains the inputs of the external field produced by a biased scanning probe microscope tip, the depolarization field produced by charged kinks, and the screening fields. According to the simulation results of the field distribution, the forward growth is caused by the step generation near the tip and the kink propagation induced by the depolarization field produced by the kinks. Scanning with the biased tip creates self-assembled domain arrays with several modes of domain length alteration: doubling, quadrupling, and chaotic. The statistical characterization of the arrays proves their high ordering. The array is formed under the influence of the depolarization field produced by three neighboring domains. The proposed mechanism can be applied for forward domain growth during switching on the polar cuts as well. In this case, the steps on the domain wall are generated on the polar surface, whereas the domain elongates by kink motion in the field produced by the charged kinks. [ABSTRACT FROM AUTHOR]

The variation in nitrogen doping concentration on the (000 1 ¯) facet of 4H-SiC single crystals grown by the physical vapor transport (PVT) growth method was investigated using Raman scattering microscopy. The observed variation was well correlated with the terrace-width variation in the step–terrace structure on the facet; regions with unevenly distributed terrace-widths always showed a lower nitrogen concentration compared to those having evenly distributed terrace-widths. It was revealed by low-energy electron channeling contrast imaging that in lower nitrogen concentration regions, terraces with two dangling bonds per silicon atom at the step riser in the step-down direction always became wider. On the basis of these experimental results, the nitrogen incorporation kinetics during PVT growth of 4H-SiC crystals was discussed. [ABSTRACT FROM AUTHOR]

Fluid convection during protein crystallization plays a significant role in determining the crystal growth rate and crystal quality. Crystals grown in reduced flow strength gives a superior quality crystal. Hence, tuning the fluid flow strength is very essential in the crystal growth process. In this work, we demonstrate a new method to suppress the flow strength using the confinement effect during the vapor diffusion method of protein crystallization where the crystal is grown inside an evaporating droplet. A flow study is carried out at four different confinement conditions to study the effect of confinement. The flow inside the droplet is caused by the evaporation induced natural convection, which is measured by the micro-PIV method. The concentration gradient generated around the growing crystal induces buoyancy driven flow around the protein crystal during the crystal growth phase. The evaporation rate from the droplet and the flow strength inside the droplet get suppressed by increasing the confinement. Hence, the flow strength can be tuned by adjusting the confinement, which is a very simple method to manipulate the flow strength inside the protein droplet. [ABSTRACT FROM AUTHOR]

This Tutorial provides an overview of the techniques that are most commonly utilized to grow bulk van der Waals crystals. The materials discussed were selected to highlight various challenges that are often encountered during crystal growth. In relatively equal parts, the text covers melt-based techniques, vapor transport growths, and the characterization of crystal quality with an emphasis on structural and chemical homogeneities. Pertinent details are given regarding the growth and characterization of many specific compounds, with examples mostly drawn from our own research, and an effort is made to highlight cases where the growths offer a particular lesson or the conditions have a significant impact on the crystal's physical properties. A primary goal is to motivate more researchers to grow crystals by providing general descriptions and considerations for different growth techniques and equipment while sharing some of our own lessons learned and best practices for the growth and characterization of layered van der Waals crystals. The Tutorial is not written solely for aspiring crystal growers, however, because any researcher who collaborates with a crystal grower can benefit from having a greater understanding and appreciation of the processes of crystal growth and materials development. [ABSTRACT FROM AUTHOR]

Perspectives about growth of bulk gallium nitride crystals, fabricating high structural quality gallium nitride wafers and the market demand for them are presented. Three basic crystal growth technologies, halide vapor phase epitaxy, sodium flux, and ammonothermal, are described. Their advantages and disadvantages, recent development, and possibilities are discussed. The main difficulty with crystallization of thick GaN is determined. Some new solutions for bulk growth are proposed. It is shown that only crystallization on high structural quality native seeds will ensure proper progress. New ideas for fabricating gallium nitride crystals and wafers with a better control of their structural properties and point defect concentration are proposed. [ABSTRACT FROM AUTHOR]

Ga2O3 is an ultrawide bandgap semiconductor with a bandgap energy of 4.5–5.3 eV (depending on its crystal structure), which is much greater than those of conventional wide bandgap semiconductors such as SiC and GaN (3.3 eV and 3.4 eV, respectively). Therefore, Ga2O3 is promising for future power device applications, and further high-performance is expected compared to those of SiC or GaN power devices, which are currently in the development stage for commercial use. Ga2O3 crystallizes into various structures. Among them, promising results have already been reported for the most stable β-Ga2O3, and for α-Ga2O3, which has the largest bandgap energy of 5.3 eV. In this article, we overview state-of-the-art technologies of β-Ga2O3 and α-Ga2O3 for future power device applications. We will give a perspective on the advantages and disadvantages of these two phases in the context of comparing the two most promising polymorphs, concerning material properties, bulk crystal growth, epitaxial growth, device fabrication, and resulting device performance. [ABSTRACT FROM AUTHOR]

Ga2O3 is an ultrawide bandgap semiconductor with a bandgap energy of 4.5–5.3 eV (depending on its crystal structure), which is much greater than those of conventional wide bandgap semiconductors such as SiC and GaN (3.3 eV and 3.4 eV, respectively). Therefore, Ga2O3 is promising for future power device applications, and further high-performance is expected compared to those of SiC or GaN power devices, which are currently in the development stage for commercial use. Ga2O3 crystallizes into various structures. Among them, promising results have already been reported for the most stable β-Ga2O3, and for α-Ga2O3, which has the largest bandgap energy of 5.3 eV. In this article, we overview state-of-the-art technologies of β-Ga2O3 and α-Ga2O3 for future power device applications. We will give a perspective on the advantages and disadvantages of these two phases in the context of comparing the two most promising polymorphs, concerning material properties, bulk crystal growth, epitaxial growth, device fabrication, and resulting device performance. [ABSTRACT FROM AUTHOR]

Crystal growth rates during laser-induced, liquid-mediated crystallization of amorphous Ge were measured with movie-mode dynamic transmission electron microscopy (MM-DTEM), a photoemission microscopy technique with nanosecond-scale time resolution. Films of 50-nm thick amorphous Ge were crystallized using a 12-ns laser pulse with a Gaussian spatial profile, which established high local temperature gradients in the specimen. Crystallization proceeded by the formation of a central zone with a high nucleation rate (zone I), followed by liquid-mediated outward growth of columnar grains (zone II), followed by spiraling growth (zone III) until the crystallization halted in cooler parts of the specimen. Zone II growth was imaged for several laser pulse energies with 20-ns electron pulses with 95 ns between frames. A thin liquid layer between the solid amorphous phase and the advancing crystallization front during zone II growth was imaged. The zone II growth rate for each experiment remained nearly constant although the crystallization front passes through a large temperature gradient. Measured growth rates ranged from 5.7 to 13.6 m/s, consistent with transient liquid layer mediated growth rather than solid-state growth. In contrast with a previous report, the growth rate did not increase systematically with laser energy or absorbed energy. The new results, together with previously reported data, suggest that both sets of experiments were conducted under conditions where the growth rate saturates near its maximum value. A phenomenological model based on the concept of upper and lower threshold temperatures for the zone II growth was fitted to the data from these experiments and previous MM-DTEM crystallization experiments. [ABSTRACT FROM AUTHOR]

A high magnetic field (HMF) was applied to the solidification process of hypereutectic Al–Sr alloy to crystallographically investigate the growth of Al4Sr crystals. The results show that the primary Al4Sr crystals exhibit typically a platelike shape in three dimensions, irrespective of whether a HMF is applied or not. They are externally bound by the faceted {001} and {011} planes (the {001} planes correspond to the large-area surfaces of the platelike shape). With the application of a HMF, the primary Al4Sr crystals tend to be distributed uniformly in the specimen and align vertically (i.e., with the longer axes parallel to the HMF direction in the observation section). Moreover, they tend to orient preferentially with the ⟨ 001 ⟩ direction (i.e., c-axes) perpendicular to the HMF direction. The platelike shape results because the {011} planes have a higher reticular density and thus faster growth rates than the {001} planes. The uniform distribution and the preferential orientations of the primary Al4Sr crystals are ascribed to the magnetic viscosity resistance force and the magnetization energy associated with the magnetocrystalline anisotropy of the Al4Sr crystals. [ABSTRACT FROM AUTHOR]

An intriguing phenomenon of electrically active defect generation is observed in homoepitaxial β-Ga2O3 films exposed to reverse bias at elevated temperatures. In particular, heating samples up to 675 K in the course of deep level transient spectroscopy measurements, i.e., with the reverse bias and voltage pulsing applied, resulted in the generation of three new levels at ∼1, ∼1.5, and ∼2 eV below the conduction band edge (labeled as E3*, E5, and E6). The corresponding defects exhibit different thermal stabilities; E5 and E6 show stability, while E3* demonstrates a remarkable metastability—it can be generated, annealed out, and regenerated in the course of sequential temperature cycles. Combining a number of annealing tests and using different types of epitaxial materials, the levels were systematically investigated, and the most credible scenario behind the phenomenon is the evolution of already existing defect configurations provoked by the applied temperature and bias. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulation of the nucleation of dislocations in the solidification of silicon has been carried out. The self-growth dislocations could be generated on growth front of grains with the reduction of local energy during homogenous nucleation and growth of silicon. The nucleation mechanism of the self-growth dislocation has been discussed; the essence of it is the mismatch of two atomic islands with different twin stacking sequences in the rough interface. Temperature could affect the interface morphology and then the generation of self-growth dislocation. In addition, some dislocations move along twin boundaries in the grain and even are absorbed by grain boundaries in the course of crystal growth. [ABSTRACT FROM AUTHOR]

Blue phase liquid crystals (BPLCs) are emerging as a promising candidate for tunable three-dimensional (3D) photonic crystals. Uniform monodomain BPLCs with a large temperature range are needed to achieve higher performance for photonic applications. Here, we experimentally demonstrated monodomain polymer stabilized blue phase liquid crystals (PS-BPLCs) induced by a long-lasting electric field. The PS-BPLCs with a single crystal orientation can be obtained with appropriate electrical treatment, and they also possess a large temperature range of 70 °C including room temperature. The physical mechanism behind their spectral properties, phase transition temperature, and the morphology of crystal growth process under different electric fields are investigated with detailed experimental analysis. This work helps further understanding of crystal nucleation and growth of PS-BPLCs in electric field and also can expedite the development of PS-BPLC based tunable 3D photonic crystal devices. [ABSTRACT FROM AUTHOR]

Pure SnSe, 5% In, 10% In, 5% Sb, and 10% Sb doped SnSe single crystals were grown by the direct vapour transport technique. The energy dispersive X-ray analysis study of the samples showed them to be near stoichiometric but slightly Sn deficient. The X-ray diffraction study of all the as-grown single crystal samples showed that they possess an orthorhombic structure and the lattice parameters are in good agreement with the reported parameters. The thermoelectric power (S), dc electrical conductivity (σ), and thermal conductivity (κ) variation with temperature from ambient to 573 K substantiated the semiconducting nature of all the five samples. The sign of "S" was positive for all five samples for all the temperature range stating the sample to be a p-type semiconductor. The power factor (S2σ) and figure of merit (ZT) variation with temperature showed that pure SnSe possesses the highest value compared to doped samples. The obtained results are studied and discussed in detail. [ABSTRACT FROM AUTHOR]

Single crystalline Ag/Fe/Fe0.5Co0.5/MgO(001) films were grown by Molecular Beam Epitaxy and investigated by Magneto-Optic Kerr Effect (MOKE). We find that even though the 4-fold magnetic anisotropies of Ag/Fe/MgO(001) and Ag/Fe0.5Co0.5/MgO(001) films are different from the corresponding bulk values, their opposite signs allow a fine tuning of the 4-fold magnetic anisotropy in Ag/Fe/Fe0.5Co0.5/MgO(001) films by varying the Fe and Fe0.5Co0.5 film thicknesses. In particular, the critical point of zero anisotropy can be achieved in a wide range of film thicknesses. Using Rotational MOKE, we determined and constructed the anisotropy phase diagram in the Fe and Fe0.5Co0.5 thickness plane from which the zero anisotropy exhibits a linear relation between the Fe and Fe0.5Co0.5 thickness. [ABSTRACT FROM AUTHOR]

The magnetocaloric effect has been studied in high quality single crystals of Fe7Se8 (3c type) grown by using Bridgman's method. Magnetization and magnetocaloric effect measurements have been carried out in a magnetic field up to 5 T over the temperature range from 2 to 490 K. The spin reorientation transition from the easy c-axis to the easy c-plane, proceeding in an abrupt fashion, as a first-order phase transition, has been observed near the temperature TR ≈ 125 K. The magnetization curves in the vicinity of this transition were shown to have an S-shape with a clear hysteresis. The first order metamagnetic field induced transitions have been identified above and below TR. The conventional magnetocaloric effect related to the metamagnetic transitions has been found above TR, while below TR the inverse magnetocaloric effect was clearly seen. The existence of both kinds of magnetocaloric effect is important from the point of view of large rotating field entropy change in Fe7Se8 single crystals. The refrigeration capacity associated with a second order phase transition from the ferrimagnetic to the paramagnetic state at the Néel temperature TN ≈ 450 K was found to be weaker than that appearing near TR. The giant anisotropy of the magnetocaloric effect was related to the magnetic anisotropy of Fe7Se8 crystals. The one-ion model of the magnetocaloric effect has been developed and its predictions have been compared with experimental data. [ABSTRACT FROM AUTHOR]

Using the traveling heater method, we have developed commercial CdZnTe (CZT) crystal growth, fabrication, and in-house test technologies for both, photon-starved gamma spectroscopic sensors and high-flux x-ray photon-counting for medical imaging and other applications. We compare the performance of different CZT material types for gamma spectroscopy and for high-flux x-ray imaging. We demonstrate single-threshold photon counting and basic imaging capability of pixelated CZT detectors at the highest x-ray fluxes we could generate in-house, i.e., ∼250 × 106 photons/(mm2 s). We show that the test system can be used for universal, absolute flux calibration of x-ray beams based on an accurate pile-up fitting algorithm. The detectors also perform spectroscopically under high-flux, when tested with energy discriminating electronics. A brief investigation on the effects of leakage, photo, and excess currents including their temporal behavior is also presented. Sub 1% uncorrected single-pixel resolution of the 662 keV 137Cs full energy peak was achieved with the gamma spectroscopy optimized material, fabricated into pixelated sensors. [ABSTRACT FROM AUTHOR]

Heteroepitaxial growth of crystalline SrZrO3 (SZO) on Ge (001) by atomic layer deposition is reported. Ge (001) surfaces are pretreated with 0.5-monolayers (ML) of Ba and an amorphous ∼3-nm SZO layer is grown from strontium bis(triisopropylcyclopentadienyl), tetrakis (dimethylamido) zirconium, and water at 225 °C. This ∼3-nm layer crystallizes at 590 °C and subsequent SZO growth at 225 °C leads to crystalline films that do not require further annealing. The film properties are investigated using X-ray photoelectron spectroscopy, x-ray diffraction, aberration-corrected electron microscopy, and capacitance-voltage measurements of metal-oxide semiconductor capacitor structures. Capacitance-voltage measurements of the SrZrO3/Ge heterojunctions reveal a dielectric constant of 30 for SrZrO3 and a leakage current density of 2.1 × 10−8 A/cm2 at 1 MV/cm with an equivalent oxide thickness of 0.8 nm. Oxygen plasma pretreatment of Ge (001), Zintl layer formation with 0.5 ML Ba, and atomic deuterium post-growth treatment were explored to lower interface trap density (Dit) and achieved a Dit of 8.56 × 1011 cm−2 eV−1. [ABSTRACT FROM AUTHOR]

Basic understanding of the fundamental processes in crystal growth as well as the structural quality of diamond synthesized by chemical vapour deposition on iridium surfaces has reached a high level for samples with (001) orientation. Diamond deposition on the alternative (111) surface is generally more challenging but of appreciable technological interest, too. In the present work, heteroepitaxy of diamond on Ir/YSZ/Si(111) with different off-axis angles and directions has been studied. During the growth of the first microns, strong and complex intrinsic stress states were rapidly formed. They restricted the range of suitable temperatures in this study to values between 830 °C and 970 °C. At low-stress conditions, the maximum growth rates were about 1 μm/h. They facilitated long-time processes which yielded pronounced structural improvements with minimum values of 0.08° for the azimuthal mosaic spread, 4 × 107 cm−2 for the dislocation density and 1.8 cm−1 for the Raman line width. This refinement is even faster than on (001) growth surfaces. It indicates substantial differences between the two crystal directions in terms of merging of mosaic blocks and annihilation of dislocations. Crystals with a thickness of up to 330 μm have been grown. The correlation of photoluminescence and μ-Raman tomograms with topography data also revealed fundamental differences in the off-axis growth between (001) and (111) orientation. Finally, the analysis of the microscopic structures at the growth surface provided the base for a model that can conclusively explain the intriguing reversal of stress tensor anisotropy caused by a simple inversion in sign of the off-axis angle. [ABSTRACT FROM AUTHOR]

We report the effects of nitrogen (N) plasma and indium (In) flux on the In adatom adsorption/desorption kinetics on a GaN(0001) surface at the relatively high plasma-assisted molecular beam epitaxy-growth temperature of 680 °C. We experimentally demonstrate that under an active N flux, the ( 3 × 3 ) R 30 ° surface reconstruction containing In and N quickly appears and the dynamically stable In adlayers sitting on this surface exhibit a continuous change from 0 to 2 MLs as a function of In flux. Compared to the bare GaN 1 × 1 surface which is stable during In exposure without an active N flux, we observed a much faster desorption for the bottom In adlayer and the absence of an In flux window corresponding to an In coverage of 1 ML. Moreover, when the In coverage exceeds 2 MLs, the desorption rates become identical for both surfaces. Finally, the importance of In surface coverage before GaN capping was shown by growing a series of InN/GaN multiple quantum well samples. The photoluminescence data show that a consistent quantum well structure is only formed if the surface is covered by excess In droplets before GaN capping. [ABSTRACT FROM AUTHOR]

The interaction of nitrogen and intrinsic point defects, vacancy (V) and self-interstitial (I), was examined by infrared absorption spectroscopy on the electron irradiated and post-annealed nitrogen doped float zone (FZ) silicon crystal. Various absorption lines were observed, at 551 cm−1 in as-grown samples, at 726 and 778 cm−1 in as-irradiated samples (Ir group), at 689 cm−1 after post-annealing at 400 °C and above (400 °C group), at 762 and 951 cm−1 after annealing at 600 °C (600 °C group), and at 714 cm−1 up to 800 °C (800 °C group). By irradiation, a part of N2 was changed into the Ir group. VN2 is the candidate for the origin of the Ir group. By the post annealing at 400 and 600 °C, a part of N2 and the Ir group were changed into the 400 °C group, to less extent at 600 °C. V2N2 is the candidate for the origin of the 400 °C group. By annealing at 600 °C, most of the Ir group turned into 400 °C and 600 °C groups. By annealing at 800 °C, N2 recovered almost completely, and most other complexes were not observed. Recently, lifetime degradation has been observed in the nitrogen doped FZ Si annealed at between 450 and 800 °C. The N-V interaction in the same temperature range revealed here will help to understand the lifetime degradation mechanism. The behavior of the 689 cm−1 line corresponded well to the lifetime degradation. [ABSTRACT FROM AUTHOR]