Jejitti Aravind Reddy, Annu Kumar Lakshya, R. Raj, L. Kumar, A. Chowdhury
Various magnetic materials (for example, ferro, ferri, antiferromagnetic) are characterized by their respective transition temperatures (for example, Curie and Néel transitions). Knowledge of these transition temperatures is vital from an application standpoint. Accurate measurements by suitable characterization techniques are needed for identifying these transitions. Several techniques have been used to identify Curie and Néel transition temperatures, with thermal methods being one of the preferred choice. These thermal methods include differential scanning calorimetry (DSC), differential thermal analysis, and thermogravimetric analysis. Although thermal analysis tools have been popularly used for examining magnetic phase transitions, still much confusion exists on their efficacy and might. This review article highlights the strength and limitations of measuring Curie and Néel transitions by thermal techniques; measurements by DSC were the most common choice in previous works. Considering the intrinsic/fundamental nature of these Curie/Néel transitions, such confusion on their measurements (by thermal techniques) and their subsequent analysis (for the order of transition) suggests that a more comprehensive understanding of the events should be an immediate future goal for the research community, at large.
{"title":"Characterizing Curie and Néel Point Phase Transitions via Thermal Techniques","authors":"Jejitti Aravind Reddy, Annu Kumar Lakshya, R. Raj, L. Kumar, A. Chowdhury","doi":"10.1002/pssb.202300008","DOIUrl":"https://doi.org/10.1002/pssb.202300008","url":null,"abstract":"Various magnetic materials (for example, ferro, ferri, antiferromagnetic) are characterized by their respective transition temperatures (for example, Curie and Néel transitions). Knowledge of these transition temperatures is vital from an application standpoint. Accurate measurements by suitable characterization techniques are needed for identifying these transitions. Several techniques have been used to identify Curie and Néel transition temperatures, with thermal methods being one of the preferred choice. These thermal methods include differential scanning calorimetry (DSC), differential thermal analysis, and thermogravimetric analysis. Although thermal analysis tools have been popularly used for examining magnetic phase transitions, still much confusion exists on their efficacy and might. This review article highlights the strength and limitations of measuring Curie and Néel transitions by thermal techniques; measurements by DSC were the most common choice in previous works. Considering the intrinsic/fundamental nature of these Curie/Néel transitions, such confusion on their measurements (by thermal techniques) and their subsequent analysis (for the order of transition) suggests that a more comprehensive understanding of the events should be an immediate future goal for the research community, at large.","PeriodicalId":20107,"journal":{"name":"physica status solidi (b)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83106518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The nonlinear optical properties of quantum dots under multidimensional confinement potential are investigated. In the framework of the effective mass approximation, the analytical formula of the optical absorption coefficient in the quantum dots is derived using the density matrix method and the iterative procedure, and the numerical results of typical Al0.3Ga0.7 As/GaAs material are calculated. Through calculation and numerical fitting, it is found that increasing temperature and the depth of limiting potential will give rise to the absorption peak to move to the high‐energy region commonly referred to as the blueshift, within a certain range of parameter variations. While reducing the range of limiting potential, quantum dot radius and the hydrostatic pressure can achieve the same effect. It is important to emphasize that variations in hydrostatic pressure and the depth of the limiting potential result in significant changes to the peak value of the optical absorption coefficient. The research results have a certain guiding significance for further study of the optical properties of quantum dots under multidimensional confinement potential and their application in practical production.
{"title":"Nonlinear Optical Properties of Al0.3Ga0.7As/GaAs Quantum Dots under Tunable Parameters","authors":"Xing Wang, Xuechao Li","doi":"10.1002/pssb.202300094","DOIUrl":"https://doi.org/10.1002/pssb.202300094","url":null,"abstract":"The nonlinear optical properties of quantum dots under multidimensional confinement potential are investigated. In the framework of the effective mass approximation, the analytical formula of the optical absorption coefficient in the quantum dots is derived using the density matrix method and the iterative procedure, and the numerical results of typical Al0.3Ga0.7 As/GaAs material are calculated. Through calculation and numerical fitting, it is found that increasing temperature and the depth of limiting potential will give rise to the absorption peak to move to the high‐energy region commonly referred to as the blueshift, within a certain range of parameter variations. While reducing the range of limiting potential, quantum dot radius and the hydrostatic pressure can achieve the same effect. It is important to emphasize that variations in hydrostatic pressure and the depth of the limiting potential result in significant changes to the peak value of the optical absorption coefficient. The research results have a certain guiding significance for further study of the optical properties of quantum dots under multidimensional confinement potential and their application in practical production.","PeriodicalId":20107,"journal":{"name":"physica status solidi (b)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88079686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Reshchikov, O. Andrieiev, M. Vorobiov, Denis O. Demchenko, B. McEwen, Shadi Shahedipour-Sandvik
GaN samples are implanted with Be and F and annealed in different conditions to activate the BeGa acceptors. Photoluminescence spectra are studied to recognize the defects. The UVLBe band with a maximum at 3.38 eV and the YLBe band with a maximum at 2.15 eV are observed and associated with Be. The sequential implantation of Be and F ions into GaN at 600 °C reduces the concentration of nitrogen vacancies (VN), as evidenced by the lack of the green luminescence band associated with the isolated nitrogen vacancy. First‐principles calculations are employed to find parameters of defects that can form after implantation.
{"title":"Photoluminescence from GaN Implanted with Be and F","authors":"M. Reshchikov, O. Andrieiev, M. Vorobiov, Denis O. Demchenko, B. McEwen, Shadi Shahedipour-Sandvik","doi":"10.1002/pssb.202300131","DOIUrl":"https://doi.org/10.1002/pssb.202300131","url":null,"abstract":"GaN samples are implanted with Be and F and annealed in different conditions to activate the BeGa acceptors. Photoluminescence spectra are studied to recognize the defects. The UVLBe band with a maximum at 3.38 eV and the YLBe band with a maximum at 2.15 eV are observed and associated with Be. The sequential implantation of Be and F ions into GaN at 600 °C reduces the concentration of nitrogen vacancies (VN), as evidenced by the lack of the green luminescence band associated with the isolated nitrogen vacancy. First‐principles calculations are employed to find parameters of defects that can form after implantation.","PeriodicalId":20107,"journal":{"name":"physica status solidi (b)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86285992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Naoya Mokutani, M. Deura, S. Mouri, K. Shojiki, S. Xiao, H. Miyake, T. Araki
GaN/AlN superlattices consisting of few‐monolayer GaN wells have attracted considerable attention for use in deep‐ultraviolet (DUV) light‐emitting devices. To avoid the formation of droplets and AlGaN interface layers, precise growth control is essential for fabricating superlattices with flat and abrupt interfaces. Herein, GaN/AlN superlattice structures are grown on face‐to‐face‐annealed sputter‐deposited AlN (FFA Sp‐AlN) template substrates using radio‐frequency plasma‐excited molecular beam epitaxy (RF‐MBE) utilizing in situ reflection high‐energy electron diffraction (RHEED) monitoring. Both AlN and GaN are grown under metal‐rich conditions, and subsequently, the droplets are eliminated by droplet elimination by radical beam irradiation (DERI) method for AlN and by growth interruption for GaN. Furthermore, the dependence of AlN thickness on the properties of superlattices is investigated. The AlN thickness changes linearly with the supply time of the Al metal; thus, the AlN thickness is easily controllable. A total of 20‐period GaN/AlN superlattices with flat and abrupt interfaces is fabricated, as confirmed using atomic force microscopy and X‐ray diffraction. Cathodoluminescence with a peak wavelength of 230–260 nm at room temperature is obtained from the fabricated superlattices. Moreover, the emission wavelength shifts with an increase in AlN thickness.
{"title":"Control of Metal‐Rich Growth for GaN/AlN Superlattice Fabrication on Face‐to‐Face‐Annealed Sputter‐Deposited AlN Templates","authors":"Naoya Mokutani, M. Deura, S. Mouri, K. Shojiki, S. Xiao, H. Miyake, T. Araki","doi":"10.1002/pssb.202300061","DOIUrl":"https://doi.org/10.1002/pssb.202300061","url":null,"abstract":"GaN/AlN superlattices consisting of few‐monolayer GaN wells have attracted considerable attention for use in deep‐ultraviolet (DUV) light‐emitting devices. To avoid the formation of droplets and AlGaN interface layers, precise growth control is essential for fabricating superlattices with flat and abrupt interfaces. Herein, GaN/AlN superlattice structures are grown on face‐to‐face‐annealed sputter‐deposited AlN (FFA Sp‐AlN) template substrates using radio‐frequency plasma‐excited molecular beam epitaxy (RF‐MBE) utilizing in situ reflection high‐energy electron diffraction (RHEED) monitoring. Both AlN and GaN are grown under metal‐rich conditions, and subsequently, the droplets are eliminated by droplet elimination by radical beam irradiation (DERI) method for AlN and by growth interruption for GaN. Furthermore, the dependence of AlN thickness on the properties of superlattices is investigated. The AlN thickness changes linearly with the supply time of the Al metal; thus, the AlN thickness is easily controllable. A total of 20‐period GaN/AlN superlattices with flat and abrupt interfaces is fabricated, as confirmed using atomic force microscopy and X‐ray diffraction. Cathodoluminescence with a peak wavelength of 230–260 nm at room temperature is obtained from the fabricated superlattices. Moreover, the emission wavelength shifts with an increase in AlN thickness.","PeriodicalId":20107,"journal":{"name":"physica status solidi (b)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75103905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
For heat‐treatable aluminum alloys, solid solute elements play key role in material strengthening. Al–Mg–Si alloy is a typical heat‐treatable alloy; Cu and Si atoms are its main solid solution atoms. To reveal the strengthening mechanism, the interaction between the edge dislocations and the Cu and Si solute atoms of different concentration in aluminum matrix is investigated by molecular dynamics (MD) simulation. Results indicate that Cu atoms provide a more effective strengthening due to the stronger pinning effect. The increment of critical resolved shear stress (ΔCRSS) is a function of concentration of solid solute atoms. When more than two types of solid solution atoms coexist in matrix, the final increment of the ΔCRSS is determined by the interactive effects of the atoms instead of the direct sum of all items. The pinning of Cu solid solute atoms can lead to two Shockley partial dislocations merging to an edge dislocation.
{"title":"Molecular Dynamics Simulation of Solution Strengthening of Si and Cu Atoms in Aluminum Alloy","authors":"Shining Kong, Jianyu Li, Zhao Zhang","doi":"10.1002/pssb.202300108","DOIUrl":"https://doi.org/10.1002/pssb.202300108","url":null,"abstract":"For heat‐treatable aluminum alloys, solid solute elements play key role in material strengthening. Al–Mg–Si alloy is a typical heat‐treatable alloy; Cu and Si atoms are its main solid solution atoms. To reveal the strengthening mechanism, the interaction between the edge dislocations and the Cu and Si solute atoms of different concentration in aluminum matrix is investigated by molecular dynamics (MD) simulation. Results indicate that Cu atoms provide a more effective strengthening due to the stronger pinning effect. The increment of critical resolved shear stress (ΔCRSS) is a function of concentration of solid solute atoms. When more than two types of solid solution atoms coexist in matrix, the final increment of the ΔCRSS is determined by the interactive effects of the atoms instead of the direct sum of all items. The pinning of Cu solid solute atoms can lead to two Shockley partial dislocations merging to an edge dislocation.","PeriodicalId":20107,"journal":{"name":"physica status solidi (b)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74669886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
CaMnO3 is a promising starting point for the search of perovskites which are suitable as electrode materials for the hydrogen evolution reaction (HER). In a previous theoretical study [Phys. Status Solidi B 2022, 260, 2200427], it was established that the global hybrid functional PW1PW is well suited to obtain structural, energetic, and electronic bulk properties. Herein, the focus is extended to surface properties of CaMnO3. All symmetry‐inequivalent low‐index surfaces of CaMnO3 are investigated with PW1PW. Based on the experience with polar surfaces, it is decided to employ stoichiometric and symmetric models, in some cases with Schottky defects. From the calculated surface energies, the crystal morphologies are predicted based on the Gibbs–Wulff theorem. The (101), (100), (011), (001), and (010) surfaces (space group no. 62) and the (010), (110), (011), and (101) surfaces (space group no. 20) dominate the surfaces of respective single crystals and should be considered in future theoretical calculations of the HER. Furthermore, it is found that the modification with space group no. 20 is significantly more stable than space group no. 62 for nanoparticles with a diameter below 10 nm.
{"title":"Effect of Surface Energetics on Phase Stability of CaMnO3","authors":"B. Grimm, T. Bredow","doi":"10.1002/pssb.202300031","DOIUrl":"https://doi.org/10.1002/pssb.202300031","url":null,"abstract":"CaMnO3 is a promising starting point for the search of perovskites which are suitable as electrode materials for the hydrogen evolution reaction (HER). In a previous theoretical study [Phys. Status Solidi B 2022, 260, 2200427], it was established that the global hybrid functional PW1PW is well suited to obtain structural, energetic, and electronic bulk properties. Herein, the focus is extended to surface properties of CaMnO3. All symmetry‐inequivalent low‐index surfaces of CaMnO3 are investigated with PW1PW. Based on the experience with polar surfaces, it is decided to employ stoichiometric and symmetric models, in some cases with Schottky defects. From the calculated surface energies, the crystal morphologies are predicted based on the Gibbs–Wulff theorem. The (101), (100), (011), (001), and (010) surfaces (space group no. 62) and the (010), (110), (011), and (101) surfaces (space group no. 20) dominate the surfaces of respective single crystals and should be considered in future theoretical calculations of the HER. Furthermore, it is found that the modification with space group no. 20 is significantly more stable than space group no. 62 for nanoparticles with a diameter below 10 nm.","PeriodicalId":20107,"journal":{"name":"physica status solidi (b)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73314312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Huaixiang Wang, D. Lu, Weipeng Wang, Yifan Ding, Yu Ji, X. Shen, Yuan Yao, Y. Long, R. Yu
The macroscopic physical properties of materials are determined by their crystal and electronic structures. Iridates have anomalous electronic structures because of the competition of comparable energies between the Coulomb repulsion of electrons and spin–orbit coupling. The polycrystalline Sr4Ir3O10 sample is successfully synthesized, which owns a trilayered perovskite structure using the high‐pressure and high‐temperature technique. The transmission electron microscopy studies give the structural evidence of Sr4Ir3O10 in real space experimentally. It is proved that tetragonal and orthorhombic structures with I4/mmm and Pbca space groups coexist in the polycrystalline Sr4Ir3O10 sample.
{"title":"Tetragonal and Orthorhombic Phases in Polycrystalline Sr4Ir3O10 Synthesized by High‐Pressure and High‐Temperature Technique","authors":"Huaixiang Wang, D. Lu, Weipeng Wang, Yifan Ding, Yu Ji, X. Shen, Yuan Yao, Y. Long, R. Yu","doi":"10.1002/pssb.202300050","DOIUrl":"https://doi.org/10.1002/pssb.202300050","url":null,"abstract":"The macroscopic physical properties of materials are determined by their crystal and electronic structures. Iridates have anomalous electronic structures because of the competition of comparable energies between the Coulomb repulsion of electrons and spin–orbit coupling. The polycrystalline Sr4Ir3O10 sample is successfully synthesized, which owns a trilayered perovskite structure using the high‐pressure and high‐temperature technique. The transmission electron microscopy studies give the structural evidence of Sr4Ir3O10 in real space experimentally. It is proved that tetragonal and orthorhombic structures with I4/mmm and Pbca space groups coexist in the polycrystalline Sr4Ir3O10 sample.","PeriodicalId":20107,"journal":{"name":"physica status solidi (b)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72687880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Pearson, J. Keller, L. Stolt, Charlotte Platzer Björkman
The stability of thin‐film solar cells spanning a wide range of compositions within the (Ag,Cu)(In,Ga)Se2 material system is evaluated over time, after dry‐heat annealing and after light soaking, and the role of Ag and Ga content is explored. Ag‐free CuInSe2 is relatively stable to annealing and storage, while Cu(In,Ga)Se2 suffers a degradation of fill factor and carrier collection. High‐Ga (Ag,Cu)(In,Ga)Se2 suffers degradation of carrier collection after prolonged annealing, reducing the short‐circuit current by ≈12%. Ga‐free (Ag,Cu)InSe2 loses up to a third of open‐circuit voltage and a quarter of fill factor after all treatments are applied. All samples suffer voltage losses after light soaking, with the Ga‐free devices losing up to 50 mV and those containing Ga losing up to 90 mV. Ag incorporation leads to a significant reduction in doping, and a significant increase in the response of doping to treatments, with the depletion width of (Ag,Cu)(In,Ga)Se2 samples expanding from ≈0.1 μm as‐grown to beyond 1.0 μm after all treatments, compared to the Cu(In,Ga)Se2 sample variation of ≈0.1–0.3 μm. Connections between Ag content, doping instability, and performance degradation are discussed.
{"title":"Investigating the Role of Ag and Ga Content in the Stability of Wide‐Gap (Ag,Cu)(In,Ga)Se2 Thin‐Film Solar Cells","authors":"P. Pearson, J. Keller, L. Stolt, Charlotte Platzer Björkman","doi":"10.1002/pssb.202300170","DOIUrl":"https://doi.org/10.1002/pssb.202300170","url":null,"abstract":"The stability of thin‐film solar cells spanning a wide range of compositions within the (Ag,Cu)(In,Ga)Se2 material system is evaluated over time, after dry‐heat annealing and after light soaking, and the role of Ag and Ga content is explored. Ag‐free CuInSe2 is relatively stable to annealing and storage, while Cu(In,Ga)Se2 suffers a degradation of fill factor and carrier collection. High‐Ga (Ag,Cu)(In,Ga)Se2 suffers degradation of carrier collection after prolonged annealing, reducing the short‐circuit current by ≈12%. Ga‐free (Ag,Cu)InSe2 loses up to a third of open‐circuit voltage and a quarter of fill factor after all treatments are applied. All samples suffer voltage losses after light soaking, with the Ga‐free devices losing up to 50 mV and those containing Ga losing up to 90 mV. Ag incorporation leads to a significant reduction in doping, and a significant increase in the response of doping to treatments, with the depletion width of (Ag,Cu)(In,Ga)Se2 samples expanding from ≈0.1 μm as‐grown to beyond 1.0 μm after all treatments, compared to the Cu(In,Ga)Se2 sample variation of ≈0.1–0.3 μm. Connections between Ag content, doping instability, and performance degradation are discussed.","PeriodicalId":20107,"journal":{"name":"physica status solidi (b)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85919082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Cai, Liangqing Zhu, Le Wang, Liyan Shang, Ya-wei Li, Jinzhong Zhang, K. Jiang, Zhigao Hu
InGaAs infrared photodetectors subjected to irradiation environments undergo microstructural modifications and concomitant degradation, yet the underlying microscopic mechanism has not been fully studied. Herein, the influence of γ irradiation (total dose of 20 krad(Si)) on an In0.53Ga0.47 As/InP p–i–n focal plane array is studied by spatially resolved and temperature‐dependent (3–290 K) photoluminescence (PL) measurements. By comparative PL studies of pre‐irradiation and post‐irradiation, the spatially resolved PL results of irradiation indicate that the in‐plane uniformity of all PL features presents bigger fluctuations, meanwhile, the results of temperature‐dependence PL demonstrate that the PL integral intensity related to impurities and interface‐bound states is significantly weakened after irradiation. This can be attributed to the enhanced migration and reaction of defects caused by γ irradiation. Some mobile defects tend to migrate to lower energy regions, such as interfaces, and form defect complexes. In addition, some impurities combine with mobile defects and form inactive impurity–defect complexes. The findings reveal the effects of low‐dose γ irradiation on InGaAs devices and may provide useful information for enhancing radiation resistance.
{"title":"γ‐Irradiation Damage Mechanism of InGaAs/InP p–i–n Focal Plane Array Investigated by Spatially Resolved and Temperature‐Dependent Photoluminescence","authors":"Y. Cai, Liangqing Zhu, Le Wang, Liyan Shang, Ya-wei Li, Jinzhong Zhang, K. Jiang, Zhigao Hu","doi":"10.1002/pssb.202200546","DOIUrl":"https://doi.org/10.1002/pssb.202200546","url":null,"abstract":"InGaAs infrared photodetectors subjected to irradiation environments undergo microstructural modifications and concomitant degradation, yet the underlying microscopic mechanism has not been fully studied. Herein, the influence of γ irradiation (total dose of 20 krad(Si)) on an In0.53Ga0.47 As/InP p–i–n focal plane array is studied by spatially resolved and temperature‐dependent (3–290 K) photoluminescence (PL) measurements. By comparative PL studies of pre‐irradiation and post‐irradiation, the spatially resolved PL results of irradiation indicate that the in‐plane uniformity of all PL features presents bigger fluctuations, meanwhile, the results of temperature‐dependence PL demonstrate that the PL integral intensity related to impurities and interface‐bound states is significantly weakened after irradiation. This can be attributed to the enhanced migration and reaction of defects caused by γ irradiation. Some mobile defects tend to migrate to lower energy regions, such as interfaces, and form defect complexes. In addition, some impurities combine with mobile defects and form inactive impurity–defect complexes. The findings reveal the effects of low‐dose γ irradiation on InGaAs devices and may provide useful information for enhancing radiation resistance.","PeriodicalId":20107,"journal":{"name":"physica status solidi (b)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86116188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The magnetic ground state of LaCrO3 and CaCrO3 solid solution is investigated in the complete miscibility range, that is, La1−xCaxCrO3 with 0 ≤ x ≤ 1 at the interval of x = 0.25 to understand the magnetic phase transitions with Ca substitutional fraction. The density functional theory is used with Hubbard correction to account for Cr exchange interaction. The isostructural La1−xCaxCrO3 system exhibits antiferromagnetic insulator (x = 0, i.e., LaCrO3) to ferromagnetic half metal (x = 0.75, i.e., La0.25Ca0.75CrO3) to antiferromagnetic metal (x = 1, i.e., CaCrO3) phase transitions. Cr changes its oxidation state from 3+ in LaCrO3 to 4+ in CaCrO3, showing both 3+ and 4+ states for intermediate compositions. Interestingly, the introduction of Hubbard energy U and Ca substitution affects Cr–O hybridization, as observed in partial density of states. A compositional phase diagram with magnetic ground state is presented for the La1−xCaxCrO3 (0 ≤ x ≤ 1) system.
{"title":"Onset of Antiferromagnetic Insulator‐to‐Ferromagnetic Half Metal‐to‐Antiferromagnetic Metal Transitions in La1−xCaxCrO3 and their Microscopic Origin","authors":"Jeel Swami, A. Dixit, B. Tiwari","doi":"10.1002/pssb.202300065","DOIUrl":"https://doi.org/10.1002/pssb.202300065","url":null,"abstract":"The magnetic ground state of LaCrO3 and CaCrO3 solid solution is investigated in the complete miscibility range, that is, La1−xCaxCrO3 with 0 ≤ x ≤ 1 at the interval of x = 0.25 to understand the magnetic phase transitions with Ca substitutional fraction. The density functional theory is used with Hubbard correction to account for Cr exchange interaction. The isostructural La1−xCaxCrO3 system exhibits antiferromagnetic insulator (x = 0, i.e., LaCrO3) to ferromagnetic half metal (x = 0.75, i.e., La0.25Ca0.75CrO3) to antiferromagnetic metal (x = 1, i.e., CaCrO3) phase transitions. Cr changes its oxidation state from 3+ in LaCrO3 to 4+ in CaCrO3, showing both 3+ and 4+ states for intermediate compositions. Interestingly, the introduction of Hubbard energy U and Ca substitution affects Cr–O hybridization, as observed in partial density of states. A compositional phase diagram with magnetic ground state is presented for the La1−xCaxCrO3 (0 ≤ x ≤ 1) system.","PeriodicalId":20107,"journal":{"name":"physica status solidi (b)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83920797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：