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http://hdl.handle.net/2115/183
2024-03-29T09:46:53ZTailored copper oxidation in alkaline aqueous solution after helium cation implantation
http://hdl.handle.net/2115/91330
Title: Tailored copper oxidation in alkaline aqueous solution after helium cation implantation
Authors: Yang, Subing; Nakagawa, Yuki; Shibayama, Tamaki
Abstract: Manipulating Cu oxidation is important for Cu anti-oxidation techniques and Cu oxide fabrication. In this study, Cu oxidation behavior after He+ implantation was observed after exposure to 0.1 M aqueous NaOH, and the underlying microstructural evolution and mechanism were investigated. He+ implantation and some C concomitantly introduced into the Cu surface accelerated formation of a thin oxide layer during the initial oxidation period, resulting in faster initial generation and more rapid growth of CuO during the subsequent oxidation. Furthermore, He+ implantation homogenized the distribution of CuO on the Cu substrate. Our findings will increase researchers' understanding of the oxidation and corrosion behavior of Cu in aqueous alkaline conditions, and provide new insights into designing and growing Cu oxide nanostructures by ion implantation.2022-06-29T15:00:00ZYang, SubingNakagawa, YukiShibayama, TamakiManipulating Cu oxidation is important for Cu anti-oxidation techniques and Cu oxide fabrication. In this study, Cu oxidation behavior after He+ implantation was observed after exposure to 0.1 M aqueous NaOH, and the underlying microstructural evolution and mechanism were investigated. He+ implantation and some C concomitantly introduced into the Cu surface accelerated formation of a thin oxide layer during the initial oxidation period, resulting in faster initial generation and more rapid growth of CuO during the subsequent oxidation. Furthermore, He+ implantation homogenized the distribution of CuO on the Cu substrate. Our findings will increase researchers' understanding of the oxidation and corrosion behavior of Cu in aqueous alkaline conditions, and provide new insights into designing and growing Cu oxide nanostructures by ion implantation.An investigation of surface contamination introduced during He plus implantation and subsequent effects on the thermal oxidation of Cu
http://hdl.handle.net/2115/90881
Title: An investigation of surface contamination introduced during He plus implantation and subsequent effects on the thermal oxidation of Cu
Authors: Yang, Subing; Nakagawa, Yuki; Shibayama, Tamaki
Abstract: Ion implantation is a potential means of increasing the oxidation resistance of Cu. However, carbonaceous contamination can also be introduced onto the metal surface during this process as a consequence of pump oil within the vacuum system. This can complicate analysis of the effect of ion implantation on Cu oxidation. The present study examined the surface contamination introduced during He+ implantation. Carbonaceous contamination was indeed identified on the Cu surface and had an obvious passivation effect on Cu oxidation at 200 °C. This was ascribed to the implantation of C into the Cu to a depth of several nanometers in conjunction with He+ implantation. The Cu was protected from oxidation by the formation of a layer consisting of C, Cu and a small amount of Cu2O that inhibited the inward diffusion of oxygen.2022-02-28T15:00:00ZYang, SubingNakagawa, YukiShibayama, TamakiIon implantation is a potential means of increasing the oxidation resistance of Cu. However, carbonaceous contamination can also be introduced onto the metal surface during this process as a consequence of pump oil within the vacuum system. This can complicate analysis of the effect of ion implantation on Cu oxidation. The present study examined the surface contamination introduced during He+ implantation. Carbonaceous contamination was indeed identified on the Cu surface and had an obvious passivation effect on Cu oxidation at 200 °C. This was ascribed to the implantation of C into the Cu to a depth of several nanometers in conjunction with He+ implantation. The Cu was protected from oxidation by the formation of a layer consisting of C, Cu and a small amount of Cu2O that inhibited the inward diffusion of oxygen.Anisotropic defect distribution in He+-irradiated 4H-SiC: Effect of stress on defect distribution
http://hdl.handle.net/2115/88735
Title: Anisotropic defect distribution in He+-irradiated 4H-SiC: Effect of stress on defect distribution
Authors: Yang, Subing; Nakagawa, Yuki; Kondo, Minako; Shibayama, Tamaki
Abstract: Irradiation-induced anisotropic swelling in hexagonal alpha-SiC is known to degrade the mechanical properties of SiC; however, the associated physical mechanism and microstructural process remain insufficiently understood. In this study, an anisotropic swelling condition where the surface normal direction was allowed to freely expand with constraint in the lateral direction was introduced in 4H-SiC using selected-area He+ irradiation, and the internal defect distribution was investigated using transmission electron microscopy (TEM) and advanced scanning TEM. The defect distribution was compared to that in non-selected-area He+-irradiated 4H-SiC and electron-irradiated TEM-foil 4H-SiC. An anisotropic defect distribution was observed in the selected-area He+-ion-irradiated 4H-SiC, with interstitial defects preferentially redistributed in the surface normal direction ([0 004]) and negative volume defects (such as vacancies and/or carbon antisite defects) dominantly located in the lateral directions ([11 (2) over bar0] and [10 (1) over bar0]). This anisotropy of the defect distribution was substantially lower in the non-selected-area He+-irradiated and electron-irradiated samples. The stress condition in the three samples was also measured and analyzed. In the selected-area He+-irradiated 4H-SiC, compressive stress was introduced in the lateral directions (([10 (1) over bar0] and [11 (2) over bar0])), with little stress introduced in the surface normal direction ([0 004]); this stress condition was introduced at the beginning of ion irradiation. The compressive stress likely inhibits the formation of interstitial defects in the lateral directions, enhancing the anisotropy of the defect distribution in SiC.2021-05-31T15:00:00ZYang, SubingNakagawa, YukiKondo, MinakoShibayama, TamakiIrradiation-induced anisotropic swelling in hexagonal alpha-SiC is known to degrade the mechanical properties of SiC; however, the associated physical mechanism and microstructural process remain insufficiently understood. In this study, an anisotropic swelling condition where the surface normal direction was allowed to freely expand with constraint in the lateral direction was introduced in 4H-SiC using selected-area He+ irradiation, and the internal defect distribution was investigated using transmission electron microscopy (TEM) and advanced scanning TEM. The defect distribution was compared to that in non-selected-area He+-irradiated 4H-SiC and electron-irradiated TEM-foil 4H-SiC. An anisotropic defect distribution was observed in the selected-area He+-ion-irradiated 4H-SiC, with interstitial defects preferentially redistributed in the surface normal direction ([0 004]) and negative volume defects (such as vacancies and/or carbon antisite defects) dominantly located in the lateral directions ([11 (2) over bar0] and [10 (1) over bar0]). This anisotropy of the defect distribution was substantially lower in the non-selected-area He+-irradiated and electron-irradiated samples. The stress condition in the three samples was also measured and analyzed. In the selected-area He+-irradiated 4H-SiC, compressive stress was introduced in the lateral directions (([10 (1) over bar0] and [11 (2) over bar0])), with little stress introduced in the surface normal direction ([0 004]); this stress condition was introduced at the beginning of ion irradiation. The compressive stress likely inhibits the formation of interstitial defects in the lateral directions, enhancing the anisotropy of the defect distribution in SiC.Oxygen Separation Performance of Ca2AlMnO5+delta as an Oxygen Storage Material for High-Temperature Pressure Swing Adsorption
http://hdl.handle.net/2115/88584
Title: Oxygen Separation Performance of Ca2AlMnO5+delta as an Oxygen Storage Material for High-Temperature Pressure Swing Adsorption
Authors: Tanahashi, Keita; Omura, Yusei; Naya, Hidekazu; Kunisada, Yuji; Sakaguchi, Norihito; Kurniawan, Ade; Nomura, Takahiro
Abstract: High-temperature pressure swing adsorption (HT-PSA) is a promising energy-saving approach for oxygen production from air. Ca2AlMnO5+delta, a Brownmillerite-type perovskite, is a promising sorbent for HT-PSA because of its remarkably high oxygen storage capacity (up to 3.3 wt%). In this study, we investigated the redox thermodynamics of Ca2AlMnO5+delta by pressure-composition-temperature (PCT) measurements and investigated the HT-PSA performance of Ca2AlMnO5+delta pellets in a 100 g-scale packed-bed-type reactor. PCT measurements revealed that Ca2AlMnO5+delta can reversibly separate 2.2 wt% of oxygen per cycle under equilibrium conditions between ambient oxygen partial pressure and 5x10-4 MPa at 525 degrees C. However, in a 5 min switching HT-PSA test, Ca2AlMnO5+delta pellets were able to reversibly separate less than 1 wt% oxygen per cycle, which is significantly lower than that estimated from the thermodynamic properties of Ca2AlMnO5+delta. On the other hand, the exothermic oxygen storage and endothermic oxygen release reactions cause significant temperature variation of the packed bed. This study clarifies that, in order to increase the energy efficiency of oxygen separation by HT-PSA, there is a need to compensate for the heat of reaction, which changes the reactor temperature in a direction that interferes with the reaction.2022-12-14T15:00:00ZTanahashi, KeitaOmura, YuseiNaya, HidekazuKunisada, YujiSakaguchi, NorihitoKurniawan, AdeNomura, TakahiroHigh-temperature pressure swing adsorption (HT-PSA) is a promising energy-saving approach for oxygen production from air. Ca2AlMnO5+delta, a Brownmillerite-type perovskite, is a promising sorbent for HT-PSA because of its remarkably high oxygen storage capacity (up to 3.3 wt%). In this study, we investigated the redox thermodynamics of Ca2AlMnO5+delta by pressure-composition-temperature (PCT) measurements and investigated the HT-PSA performance of Ca2AlMnO5+delta pellets in a 100 g-scale packed-bed-type reactor. PCT measurements revealed that Ca2AlMnO5+delta can reversibly separate 2.2 wt% of oxygen per cycle under equilibrium conditions between ambient oxygen partial pressure and 5x10-4 MPa at 525 degrees C. However, in a 5 min switching HT-PSA test, Ca2AlMnO5+delta pellets were able to reversibly separate less than 1 wt% oxygen per cycle, which is significantly lower than that estimated from the thermodynamic properties of Ca2AlMnO5+delta. On the other hand, the exothermic oxygen storage and endothermic oxygen release reactions cause significant temperature variation of the packed bed. This study clarifies that, in order to increase the energy efficiency of oxygen separation by HT-PSA, there is a need to compensate for the heat of reaction, which changes the reactor temperature in a direction that interferes with the reaction.Developing Composite Phase Change Material with Al-Si Base Microencapsulated Phase Change Material and Glass Frit for High Temperature Applications
http://hdl.handle.net/2115/88544
Title: Developing Composite Phase Change Material with Al-Si Base Microencapsulated Phase Change Material and Glass Frit for High Temperature Applications
Authors: Kawaguchi, Takahiro; Sakai, Hiroki; Shimizu, Yuto; Dong, Kaixin; Kurniawan, Ade; Nomura, Takahiro
Abstract: To achieve high energy efficiency and CO2 reduction during iron- and steelmaking, thermal management is vital. Use of phase change material (PCMs) to store excess energy in the form of latent heat has the potential to realize excellent thermal management. Microencapsulated PCMs (MEPCMs) consisting of an alloy PCM core and an oxide coating have improved corrosion resistance and are easy to mix with other materials. Conventionally, composite PCM pellets are fabricated by mixing glass frit (to aid sintering) with Al-25 mass% Si MEPCM. However, this process has not yet been optimized. In this study, the optimal stoichiometry of composite PCMs prepared using Al-25 mass% Si MEPCM and glass frit was investigated. The pellets were prepared by mixing with glass frit at 60, 80 and 90 mass% of MEPCM, followed by molding and heat treatment. As a result, pellets were successfully fabricated with condition including 60 and 80 mass% of MEPCM. The latent heat capacity of the composite PCM was 146 J g(-1), which was at least 1.59 times higher than that of existing sensible heat storage (SHS) materials. Moreover, the composite PCMs withstood 300 melting and solidification cycles. In summary, composite PCMs with excellent latent heat capacity and durability were successfully prepared.2022-12-14T15:00:00ZKawaguchi, TakahiroSakai, HirokiShimizu, YutoDong, KaixinKurniawan, AdeNomura, TakahiroTo achieve high energy efficiency and CO2 reduction during iron- and steelmaking, thermal management is vital. Use of phase change material (PCMs) to store excess energy in the form of latent heat has the potential to realize excellent thermal management. Microencapsulated PCMs (MEPCMs) consisting of an alloy PCM core and an oxide coating have improved corrosion resistance and are easy to mix with other materials. Conventionally, composite PCM pellets are fabricated by mixing glass frit (to aid sintering) with Al-25 mass% Si MEPCM. However, this process has not yet been optimized. In this study, the optimal stoichiometry of composite PCMs prepared using Al-25 mass% Si MEPCM and glass frit was investigated. The pellets were prepared by mixing with glass frit at 60, 80 and 90 mass% of MEPCM, followed by molding and heat treatment. As a result, pellets were successfully fabricated with condition including 60 and 80 mass% of MEPCM. The latent heat capacity of the composite PCM was 146 J g(-1), which was at least 1.59 times higher than that of existing sensible heat storage (SHS) materials. Moreover, the composite PCMs withstood 300 melting and solidification cycles. In summary, composite PCMs with excellent latent heat capacity and durability were successfully prepared.Ironmaking Using Municipal Solid Waste (MSW) as Reducing Agent: A Preliminary Investigation on MSW Decomposition and Ore Reduction Behavior
http://hdl.handle.net/2115/88539
Title: Ironmaking Using Municipal Solid Waste (MSW) as Reducing Agent: A Preliminary Investigation on MSW Decomposition and Ore Reduction Behavior
Authors: Hasegawa, Hiroki; Kurniawan, Ade; Iwamoto, Itsuki; Cahyono, Rochim Bakti; Budiman, Arief; Kashiwaya, Yoshiaki; Nomura, Takahiro
Abstract: The iron and steel industries currently face the depletion of high-grade ore and high CO2 emissions. Some initiatives that effectively utilize alternative carbon sources and abundant low-grade ores become the preferable solutions. This novel study aims to utilize municipal solid waste (MSW) as a reducing agent in ironmaking using low-grade (goethite) ores. As an initial fundamental approach, the comparison of decomposition behaviors between the model and actual MSW was investigated in thermogravimetric analysis. Both model and actual MSWs mainly decompose at 300-500 degrees C. As for reduction tests, pellets containing MSWs and ores with different pretreatments were prepared. The pellets were reduced in an Ar atmosphere at different temperatures. The effect of different ores: high-grade and low-grade ones, on the decomposition of MSW and the iron reduction, were investigated. As a result, interestingly, the low-grade, goethite ore-containing pellet exhibits a more significant reduction degree than the high-grade ones. The reduction is completed in 5 minutes at 700 degrees C and above, indicating a significant reduction by the decomposed carbon. The reduction degree extends at elevated temperature, which reaches more than 94% at 900 degrees C.2022-12-14T15:00:00ZHasegawa, HirokiKurniawan, AdeIwamoto, ItsukiCahyono, Rochim BaktiBudiman, AriefKashiwaya, YoshiakiNomura, TakahiroThe iron and steel industries currently face the depletion of high-grade ore and high CO2 emissions. Some initiatives that effectively utilize alternative carbon sources and abundant low-grade ores become the preferable solutions. This novel study aims to utilize municipal solid waste (MSW) as a reducing agent in ironmaking using low-grade (goethite) ores. As an initial fundamental approach, the comparison of decomposition behaviors between the model and actual MSW was investigated in thermogravimetric analysis. Both model and actual MSWs mainly decompose at 300-500 degrees C. As for reduction tests, pellets containing MSWs and ores with different pretreatments were prepared. The pellets were reduced in an Ar atmosphere at different temperatures. The effect of different ores: high-grade and low-grade ones, on the decomposition of MSW and the iron reduction, were investigated. As a result, interestingly, the low-grade, goethite ore-containing pellet exhibits a more significant reduction degree than the high-grade ones. The reduction is completed in 5 minutes at 700 degrees C and above, indicating a significant reduction by the decomposed carbon. The reduction degree extends at elevated temperature, which reaches more than 94% at 900 degrees C.Optimized Preparation of a Low-Working-Temperature Gallium Metal-Based Microencapsulated Phase Change Material
http://hdl.handle.net/2115/86728
Title: Optimized Preparation of a Low-Working-Temperature Gallium Metal-Based Microencapsulated Phase Change Material
Authors: Dong, Kaixin; Kawaguchi, Takahiro; Shimizu, Yuto; Sakai, Hiroki; Nomura, Takahiro
Abstract: Gallium has been considered for application in the thermal management of electronic equipment because of its high heat transfer ability and heat storage density. To address the issues of metal corrosion and leakage, a microencapsulation method, through which a stable corrosion-resistant ceramic shell can be formed from the liquid metal, is proposed. In this study, an optimized fabrication method for a microencapsulated phase change material (MEPCM) consisting of liquid-state Ga droplets, possessing high durability and heat storage density, is presented. A fabrication route comprising particle formation, hydrothermal treatment, and calcination is proposed. In particular, the thickness and crystal size of the GaOOH shell are controlled by changing the pH during hydrothermal treatment to produce a highly durable shell. The morphology and microstructure, phase composition, heat storage capacity, and durability of the prepared Ga-MEPCM are investigated. In addition, treatment conditions and the shell formation mechanism are analyzed. The results show that pH 9 is the most suitable shell-forming condition, at which the thickest Ga2O3 shell with the smallest crystal size can be produced, which is beneficial for ensuring durability. The MEPCM achieved 200 cycles without leakage and 300 cycles without shape deformation with a high heat storage density of 369.4 J.cm(-3).2022-08-06T15:00:00ZDong, KaixinKawaguchi, TakahiroShimizu, YutoSakai, HirokiNomura, TakahiroGallium has been considered for application in the thermal management of electronic equipment because of its high heat transfer ability and heat storage density. To address the issues of metal corrosion and leakage, a microencapsulation method, through which a stable corrosion-resistant ceramic shell can be formed from the liquid metal, is proposed. In this study, an optimized fabrication method for a microencapsulated phase change material (MEPCM) consisting of liquid-state Ga droplets, possessing high durability and heat storage density, is presented. A fabrication route comprising particle formation, hydrothermal treatment, and calcination is proposed. In particular, the thickness and crystal size of the GaOOH shell are controlled by changing the pH during hydrothermal treatment to produce a highly durable shell. The morphology and microstructure, phase composition, heat storage capacity, and durability of the prepared Ga-MEPCM are investigated. In addition, treatment conditions and the shell formation mechanism are analyzed. The results show that pH 9 is the most suitable shell-forming condition, at which the thickest Ga2O3 shell with the smallest crystal size can be produced, which is beneficial for ensuring durability. The MEPCM achieved 200 cycles without leakage and 300 cycles without shape deformation with a high heat storage density of 369.4 J.cm(-3).The origin of opto-functional enhancement in ZnO/CuO nanoforest structure fabricated by submerged photosynthesis
http://hdl.handle.net/2115/85719
Title: The origin of opto-functional enhancement in ZnO/CuO nanoforest structure fabricated by submerged photosynthesis
Authors: Takahashi, Yuki; Jeem, Melbert; Zhang, Lihua; Watanabe, Seiichi
Abstract: Semiconductor hetero-nanostructures are of great interest for practical industry use. In this report, we demonstrated ZnO/CuO nanoforest (NFRs) fabricated by galvanic submerged photo-synthesis (G-SPSC) method, which utilizes light illumination in pure water without additives. For the first time, we elucidated the origin of its enhanced opto-functional properties. At the hetero-epitaxial interface, ZnO(001)/CuO(001) planes linkage were established, even though with 13.62 - 28.15% local lattice discrepancies along the c axis. Formed under Zn rich condition and photo-induced {110} ZnO surface, the NFRs exhibited photoluminescence emissions at 450 nm and 650 nm, due to zinc interstitial (I-Zn) and oxygen vacancies (V-O). Ternary oxide of ZnCuO2 was discovered. The interface exhibited significant emission at 650 - 700 nm and absorbance at 450 - 500 nm. On the basis of STEM-VEELS spectra and ab initio calculations, electrons occupancy at Cu 3p was responsible for 2.0 eV peak of the interface absorption coefficient. In particular, an interface dipole under interface-induced gap states (IFIGS) was clarified, caused by quasi defects zinc antisite (Zn-O). This led to an incommensurate charge density (ICCD) for a coherent ZnO(001)/CuO(001) interface. This is the origin for the opto-functional enhancement of the ZnO/CuO NFRs, where a maximum 12% IPCE at 550 nm, a 20% increase from similar NFRs morphology was demonstrated. Our results indicated a promising method and strategy for novel hetero-epitaxial nanostructures fabrication in the field of optoelectrical devices. (C) 2021 The Author(s). Published by Elsevier Ltd.2022-02-28T15:00:00ZTakahashi, YukiJeem, MelbertZhang, LihuaWatanabe, SeiichiSemiconductor hetero-nanostructures are of great interest for practical industry use. In this report, we demonstrated ZnO/CuO nanoforest (NFRs) fabricated by galvanic submerged photo-synthesis (G-SPSC) method, which utilizes light illumination in pure water without additives. For the first time, we elucidated the origin of its enhanced opto-functional properties. At the hetero-epitaxial interface, ZnO(001)/CuO(001) planes linkage were established, even though with 13.62 - 28.15% local lattice discrepancies along the c axis. Formed under Zn rich condition and photo-induced {110} ZnO surface, the NFRs exhibited photoluminescence emissions at 450 nm and 650 nm, due to zinc interstitial (I-Zn) and oxygen vacancies (V-O). Ternary oxide of ZnCuO2 was discovered. The interface exhibited significant emission at 650 - 700 nm and absorbance at 450 - 500 nm. On the basis of STEM-VEELS spectra and ab initio calculations, electrons occupancy at Cu 3p was responsible for 2.0 eV peak of the interface absorption coefficient. In particular, an interface dipole under interface-induced gap states (IFIGS) was clarified, caused by quasi defects zinc antisite (Zn-O). This led to an incommensurate charge density (ICCD) for a coherent ZnO(001)/CuO(001) interface. This is the origin for the opto-functional enhancement of the ZnO/CuO NFRs, where a maximum 12% IPCE at 550 nm, a 20% increase from similar NFRs morphology was demonstrated. Our results indicated a promising method and strategy for novel hetero-epitaxial nanostructures fabrication in the field of optoelectrical devices. (C) 2021 The Author(s). Published by Elsevier Ltd.Evolution of Mercury from Iron Ores in Temperature-Programmed Heat Treatments
http://hdl.handle.net/2115/85177
Title: Evolution of Mercury from Iron Ores in Temperature-Programmed Heat Treatments
Authors: Bud, Javzandolgor; Mochizuki, Yuuki; Tsubouchi, Naoto
Abstract: The behavior of Hg released from iron ores during temperature-programmed heat treatments (TPHTs) in air has been mainly studied using an online monitoring method. The Hg release behavior in TPHT significantly depends on the type of ore being processed, which includes forms evolved as Hg-0 and Hg2+, and forms that remain thermally stable up to 950 degrees C. In addition, the TPHT experiments for model Hg compounds suggested the presence of several types of Hg forms (HgCl2, Hg2Cl2, HgS, HgO, HgSO4, and associated mineral-Hg) in the iron ores used. The amounts and proportions of suggested forms of Hg species substantially depend on the type and composition of the iron ore used. These observations may be important in designing an efficient method for the removal of Hg from iron ore and gaseous Hg.2022-01-14T15:00:00ZBud, JavzandolgorMochizuki, YuukiTsubouchi, NaotoThe behavior of Hg released from iron ores during temperature-programmed heat treatments (TPHTs) in air has been mainly studied using an online monitoring method. The Hg release behavior in TPHT significantly depends on the type of ore being processed, which includes forms evolved as Hg-0 and Hg2+, and forms that remain thermally stable up to 950 degrees C. In addition, the TPHT experiments for model Hg compounds suggested the presence of several types of Hg forms (HgCl2, Hg2Cl2, HgS, HgO, HgSO4, and associated mineral-Hg) in the iron ores used. The amounts and proportions of suggested forms of Hg species substantially depend on the type and composition of the iron ore used. These observations may be important in designing an efficient method for the removal of Hg from iron ore and gaseous Hg.Non-destructive evaluation of the strain distribution in selected-area He+ ion irradiated 4H-SiC
http://hdl.handle.net/2115/83831
Title: Non-destructive evaluation of the strain distribution in selected-area He+ ion irradiated 4H-SiC
Authors: Yang, Subing; Tokunaga, Sakiko; Kondo, Minako; Nakagawa, Yuki; Shibayama, Tamaki
Abstract: Residual strain in silicon carbide (SiC) greatly affects its physical and chemical properties and thus the performance of SiC-based devices. Herein, the detailed strain distribution in selected-area He+ ion-irradiated 4H-SiC was evaluated using the non-destructive techniques of electron backscattering diffraction and confocal Raman microscopy (CRM). In addition to the strain introduced in the irradiated area, excessive strain induced by irradiation-induced swelling also extended into the surrounding substrate. Furthermore, great compressive strain was concentrated around the interface between the irradiated and unirradiated areas. In the strain-introduced substrate, an A(1)(LO)/A(1)(LOPC) peak variation was detected by CRM, suggesting a variation of the carrier density.2020-01-14T15:00:00ZYang, SubingTokunaga, SakikoKondo, MinakoNakagawa, YukiShibayama, TamakiResidual strain in silicon carbide (SiC) greatly affects its physical and chemical properties and thus the performance of SiC-based devices. Herein, the detailed strain distribution in selected-area He+ ion-irradiated 4H-SiC was evaluated using the non-destructive techniques of electron backscattering diffraction and confocal Raman microscopy (CRM). In addition to the strain introduced in the irradiated area, excessive strain induced by irradiation-induced swelling also extended into the surrounding substrate. Furthermore, great compressive strain was concentrated around the interface between the irradiated and unirradiated areas. In the strain-introduced substrate, an A(1)(LO)/A(1)(LOPC) peak variation was detected by CRM, suggesting a variation of the carrier density.