Pub Date : 2026-01-03DOI: 10.1007/s13391-025-00625-0
Bona Lee, Sangwoo Ryu
The continuous miniaturization and increased integration density of semiconductor devices have intensified the demand for high thermal conductivity materials capable of efficiently dissipating heat generated within chips. Boron arsenide (BAs), predicted to exhibit an exceptionally high theoretical thermal conductivity of approximately 1000 W/m·K, has emerged as a promising next-generation thermal management material. However, studies on the synthesis of high-purity BAs powders and their applicability remain limited. In this work, BAs powder was synthesized via a solid-state reaction in vacuum, and the effects of annealing temperature and precursor molar ratio on phase formation and chemical composition were systematically investigated. Structural and compositional analysis revealed that annealing at 800 °C for 12 h with 2.02 mmol boron and 5.05 mmol arsenic yielded spherical, single-phase BAs with minimized B12As2 impurities and residual boron, representing the composition closest to the ideal 1:1 stoichiometry. Using the synthesized powder, BAs ceramics were fabricated via spark plasma sintering. Thermally stable ceramic discs without cracks were successfully obtained at 700 °C and 30 MPa, exhibiting a relatively low thermal conductivity of approximately 3.0 W/m·K at room temperature. When the synthesized powder was incorporated into epoxy for underfill applications, BAs/epoxy composites showed processable viscosities of 13–43 Pa·s, while their thermal conductivity increased from 0.250 to 0.416 W/m·K with increasing BAs filler content.
{"title":"Massive Synthesis in Vacuum of High Thermal Conductivity Boron Arsenide for Underfill Application","authors":"Bona Lee, Sangwoo Ryu","doi":"10.1007/s13391-025-00625-0","DOIUrl":"10.1007/s13391-025-00625-0","url":null,"abstract":"<div><p>The continuous miniaturization and increased integration density of semiconductor devices have intensified the demand for high thermal conductivity materials capable of efficiently dissipating heat generated within chips. Boron arsenide (BAs), predicted to exhibit an exceptionally high theoretical thermal conductivity of approximately 1000 W/m·K, has emerged as a promising next-generation thermal management material. However, studies on the synthesis of high-purity BAs powders and their applicability remain limited. In this work, BAs powder was synthesized via a solid-state reaction in vacuum, and the effects of annealing temperature and precursor molar ratio on phase formation and chemical composition were systematically investigated. Structural and compositional analysis revealed that annealing at 800 °C for 12 h with 2.02 mmol boron and 5.05 mmol arsenic yielded spherical, single-phase BAs with minimized B<sub>12</sub>As<sub>2</sub> impurities and residual boron, representing the composition closest to the ideal 1:1 stoichiometry. Using the synthesized powder, BAs ceramics were fabricated via spark plasma sintering. Thermally stable ceramic discs without cracks were successfully obtained at 700 °C and 30 MPa, exhibiting a relatively low thermal conductivity of approximately 3.0 W/m·K at room temperature. When the synthesized powder was incorporated into epoxy for underfill applications, BAs/epoxy composites showed processable viscosities of 13–43 Pa·s, while their thermal conductivity increased from 0.250 to 0.416 W/m·K with increasing BAs filler content.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":536,"journal":{"name":"Electronic Materials Letters","volume":"22 2","pages":"157 - 165"},"PeriodicalIF":2.6,"publicationDate":"2026-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147336567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-17DOI: 10.1007/s13391-025-00616-1
V. Raja Preethi, Sagarika Sahoo, Ryun Kyung Lee, Kee-Sun Lee
Photocatalytic WO3 materials with visible light responsiveness have attracted interest in eco-friendly wastewater treatment, antimicrobial applications, and indoor air purification. In this study, WO3/amorphous carbon dot composite coatings were produced on glass substrates using an ultrasonic spray deposition followed by heat treatment, enabling scalable and cost-effective large-area immobilized product. The precursor suspension combined hydrothermally synthesized WO3 nano cubes with citric acid (CA), which served as a carbon source. Drying and heat treatment induced carbonization of CA, resulting in a crack-free, adherent composite thin coatings comprising WO3 nano cubes interconnected by localized amorphous carbon dots (aCDs), as confirmed by Raman, FTIR, and HRTEM analyses. The carbonaceous bridges enhanced interparticle connectivity and coating adhesion to the substrate. Photocatalytic degradation of methylene blue under visible light (Xenon lamp) achieved 95% reduction in 200 min in basic pH. Photoluminescence spectroscopy confirmed synergistic interaction between WO3, and carbon dots promotes charge separation improving photocatalytic efficiency. Since the catalysts are stuck on the glass substrate surface compactly, the reusability becomes easier. This immobilized WO3/Carbon composite coating demonstrates promising potential for environmentally sustainable photocatalytic applications.
{"title":"Photocatalytic WO3/Amorphous Carbon Dots Composite Coatings Immobilized by Ultrasonic Spray on Glass Substrate","authors":"V. Raja Preethi, Sagarika Sahoo, Ryun Kyung Lee, Kee-Sun Lee","doi":"10.1007/s13391-025-00616-1","DOIUrl":"10.1007/s13391-025-00616-1","url":null,"abstract":"<div><p>Photocatalytic WO<sub>3</sub> materials with visible light responsiveness have attracted interest in eco-friendly wastewater treatment, antimicrobial applications, and indoor air purification. In this study, WO<sub>3</sub>/amorphous carbon dot composite coatings were produced on glass substrates using an ultrasonic spray deposition followed by heat treatment, enabling scalable and cost-effective large-area immobilized product. The precursor suspension combined hydrothermally synthesized WO<sub>3</sub> nano cubes with citric acid (CA), which served as a carbon source. Drying and heat treatment induced carbonization of CA, resulting in a crack-free, adherent composite thin coatings comprising WO<sub>3</sub> nano cubes interconnected by localized amorphous carbon dots (aCDs), as confirmed by Raman, FTIR, and HRTEM analyses. The carbonaceous bridges enhanced interparticle connectivity and coating adhesion to the substrate. Photocatalytic degradation of methylene blue under visible light (Xenon lamp) achieved 95% reduction in 200 min in basic pH. Photoluminescence spectroscopy confirmed synergistic interaction between WO<sub>3,</sub> and carbon dots promotes charge separation improving photocatalytic efficiency. Since the catalysts are stuck on the glass substrate surface compactly, the reusability becomes easier. This immobilized WO<sub>3</sub>/Carbon composite coating demonstrates promising potential for environmentally sustainable photocatalytic applications.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":536,"journal":{"name":"Electronic Materials Letters","volume":"22 2","pages":"146 - 156"},"PeriodicalIF":2.6,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147339719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-24DOI: 10.1007/s13391-025-00615-2
Chaeyoun Kim, Yunsu Jang, Hyun S. Kum, Byungha Shin
Indium gallium arsenide (InGaAs) is a III–V compound semiconductor with high electron mobility and a narrow bandgap, widely employed in high-speed electronic and optoelectronic devices. However, the intrinsic transport properties of InGaAs, particularly the quantitative understanding of dopant ionization and scattering mechanisms, remain insufficiently explored. In this study, we employed a rotating parallel dipole line (PDL) magnetic system in combination with a Hall bar geometry to investigate the transport properties of Si-doped In0.53Ga0.47As thin films over the temperature range of 170–340 K. The measured mobility exhibited a temperature dependence of µ ∼ T− 0.94, confirming phonon-dominated scattering, while the carrier concentration increased with temperature due to donor freeze-out behavior. An Arrhenius analysis yielded a donor activation energy of approximately 6.8 meV, corresponding to a shallow Si donor level and showing good agreement with theoretical predictions. These findings provide direct insight into the intrinsic transport characteristics of In0.53Ga0.47As and offer valuable reference data for the future design of high-speed electronic and optoelectronic devices.
{"title":"Intrinsic Transport Properties of Si-Doped In0.53Ga0.47As Revealed by Variable-Temperature Parallel Dipole Line Hall Measurements","authors":"Chaeyoun Kim, Yunsu Jang, Hyun S. Kum, Byungha Shin","doi":"10.1007/s13391-025-00615-2","DOIUrl":"10.1007/s13391-025-00615-2","url":null,"abstract":"<div><p>Indium gallium arsenide (InGaAs) is a III–V compound semiconductor with high electron mobility and a narrow bandgap, widely employed in high-speed electronic and optoelectronic devices. However, the intrinsic transport properties of InGaAs, particularly the quantitative understanding of dopant ionization and scattering mechanisms, remain insufficiently explored. In this study, we employed a rotating parallel dipole line (PDL) magnetic system in combination with a Hall bar geometry to investigate the transport properties of Si-doped In<sub>0.53</sub>Ga<sub>0.47</sub>As thin films over the temperature range of 170–340 K. The measured mobility exhibited a temperature dependence of µ ∼ T<sup>− 0.94</sup>, confirming phonon-dominated scattering, while the carrier concentration increased with temperature due to donor freeze-out behavior. An Arrhenius analysis yielded a donor activation energy of approximately 6.8 meV, corresponding to a shallow Si donor level and showing good agreement with theoretical predictions. These findings provide direct insight into the intrinsic transport characteristics of In<sub>0.53</sub>Ga<sub>0.47</sub>As and offer valuable reference data for the future design of high-speed electronic and optoelectronic devices.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":536,"journal":{"name":"Electronic Materials Letters","volume":"22 2","pages":"187 - 193"},"PeriodicalIF":2.6,"publicationDate":"2025-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13391-025-00615-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147341942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-22DOI: 10.1007/s13391-025-00612-5
Yoona Hwang, Jeongbin Lee, Hojun Kim, Boyun Choi, Seongho Kim, Nari Jeon, Jihun Mun, Hyeong-U Kim, Min Sup Choi
Two-dimensional (2D) materials, due to their atomically thin structure, are highly susceptible to environmental degradation such as oxidation and moisture absorption. These effects can significantly reduce performance and stability, making surface passivation a critical requirement for practical applications. In this work, we investigate the effects of high-k hafnium dioxide (HfO2) dielectric deposited by atomic layer deposition on transition metal dichalcogenides (TMDs), including MoTe2, MoS2, and WSe2. To enable uniform dielectric growth and interfacial bonding, oxygen plasma pre-treatments are applied to form reactive sites prior to deposition. Atomic force microscopy confirmed that the surface roughness of HfO2 decreases with longer plasma treatment, indicating improved nucleation and conformal coverage on the TMDs surface. Electrical measurements of back-gated field-effect transistors demonstrate a clear dependence of doping behavior on HfO2 thickness. In thicker films, electrons supplied from oxygen vacancies within HfO2 to the TMDs channel increases. Additionally, electrons are further induced into the channel by the positive fixed charge, resulting in strong n-type doping effects for thicker HfO2 layers, as evidenced by the enhanced n-type on-state current. In contrast, devices with thinner HfO2 films exhibit weaker n-type doping effect or even p-type behavior, likely due to the dominant influence of plasma-induced surface modifications. These results indicate the importance of optimizing both plasma treatment conditions and dielectric thickness to achieve desirable doping and passivation effects. Overall, this study presents a viable strategy for controlled the integration of high-k dielectrics with 2D semiconductors, contributing to the advancement of stable, scalable, and high-performance 2D electronic devices.
{"title":"Doping and Passivation Effects in Transition Metal Dichalcogenides via HfO2 Thin Film Deposition","authors":"Yoona Hwang, Jeongbin Lee, Hojun Kim, Boyun Choi, Seongho Kim, Nari Jeon, Jihun Mun, Hyeong-U Kim, Min Sup Choi","doi":"10.1007/s13391-025-00612-5","DOIUrl":"10.1007/s13391-025-00612-5","url":null,"abstract":"<p>Two-dimensional (2D) materials, due to their atomically thin structure, are highly susceptible to environmental degradation such as oxidation and moisture absorption. These effects can significantly reduce performance and stability, making surface passivation a critical requirement for practical applications. In this work, we investigate the effects of high-k hafnium dioxide (HfO<sub>2</sub>) dielectric deposited by atomic layer deposition on transition metal dichalcogenides (TMDs), including MoTe<sub>2</sub>, MoS<sub>2</sub>, and WSe<sub>2</sub>. To enable uniform dielectric growth and interfacial bonding, oxygen plasma pre-treatments are applied to form reactive sites prior to deposition. Atomic force microscopy confirmed that the surface roughness of HfO<sub>2</sub> decreases with longer plasma treatment, indicating improved nucleation and conformal coverage on the TMDs surface. Electrical measurements of back-gated field-effect transistors demonstrate a clear dependence of doping behavior on HfO<sub>2</sub> thickness. In thicker films, electrons supplied from oxygen vacancies within HfO<sub>2</sub> to the TMDs channel increases. Additionally, electrons are further induced into the channel by the positive fixed charge, resulting in strong n-type doping effects for thicker HfO<sub>2</sub> layers, as evidenced by the enhanced n-type on-state current. In contrast, devices with thinner HfO<sub>2</sub> films exhibit weaker n-type doping effect or even p-type behavior, likely due to the dominant influence of plasma-induced surface modifications. These results indicate the importance of optimizing both plasma treatment conditions and dielectric thickness to achieve desirable doping and passivation effects. Overall, this study presents a viable strategy for controlled the integration of high-k dielectrics with 2D semiconductors, contributing to the advancement of stable, scalable, and high-performance 2D electronic devices.</p>","PeriodicalId":536,"journal":{"name":"Electronic Materials Letters","volume":"22 2","pages":"122 - 131"},"PeriodicalIF":2.6,"publicationDate":"2025-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147341166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-22DOI: 10.1007/s13391-025-00609-0
Youngjun Cho, Heeyoung Kwack, Taehoon Kim, Kilsoo Lee, Gwangmook Kim, Donyoung Kang, Hyungsuk Lee, Wooyoung Shim
A fully printed, flexible capacitive pressure sensor was developed using standard desktop inkjet and laser printers on paper. The device consists of printed silver nanoparticle electrodes and a toner–silica nanoparticle composite dielectric layer. A unique microisland-like dielectric structure is formed during laser printing due to heterogeneous particle mixing and selective thermal fusion, resulting in rough surfaces with embedded air gaps. This morphology enhances sensitivity and accelerates response by allowing partial interlocking and compression under applied pressure. The sensor achieves a high sensitivity of 0.08 kPa−1 in the low-pressure range (< 30 kPa), fast response and recovery times (~ 50 ms), and maintains mechanical durability over 2000 loading cycles. A 144-pixel sensor array demonstrates scalability, and multifunctional input applications are enabled, including pressure-sensitive trackpads and keyboards where soft and hard touches correspond to distinct commands. This all-printing fabrication approach eliminates the need for microfabrication or complex post-processing, providing a cost-effective, scalable, and versatile method for flexible electronics. The printed pressure sensors offer a promising solution for next-generation human–machine interfaces and customizable paper-based electronic devices.
{"title":"All-Printing Based, Capacitive Pressure Sensors on Paper","authors":"Youngjun Cho, Heeyoung Kwack, Taehoon Kim, Kilsoo Lee, Gwangmook Kim, Donyoung Kang, Hyungsuk Lee, Wooyoung Shim","doi":"10.1007/s13391-025-00609-0","DOIUrl":"10.1007/s13391-025-00609-0","url":null,"abstract":"<div><p>A fully printed, flexible capacitive pressure sensor was developed using standard desktop inkjet and laser printers on paper. The device consists of printed silver nanoparticle electrodes and a toner–silica nanoparticle composite dielectric layer. A unique microisland-like dielectric structure is formed during laser printing due to heterogeneous particle mixing and selective thermal fusion, resulting in rough surfaces with embedded air gaps. This morphology enhances sensitivity and accelerates response by allowing partial interlocking and compression under applied pressure. The sensor achieves a high sensitivity of 0.08 kPa<sup>−1</sup> in the low-pressure range (< 30 kPa), fast response and recovery times (~ 50 ms), and maintains mechanical durability over 2000 loading cycles. A 144-pixel sensor array demonstrates scalability, and multifunctional input applications are enabled, including pressure-sensitive trackpads and keyboards where soft and hard touches correspond to distinct commands. This all-printing fabrication approach eliminates the need for microfabrication or complex post-processing, providing a cost-effective, scalable, and versatile method for flexible electronics. The printed pressure sensors offer a promising solution for next-generation human–machine interfaces and customizable paper-based electronic devices.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><img></picture></div></div></figure></div></div>","PeriodicalId":536,"journal":{"name":"Electronic Materials Letters","volume":"22 2","pages":"179 - 186"},"PeriodicalIF":2.6,"publicationDate":"2025-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147341159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
YPO4 nanophosphors doped with Tb3+, Ce3+, and co-doped with Tb3+/Ce3+ were synthesized via a hydrothermal method, and the effects of rare-earth doping on their structural and optical properties were comprehensively examined. A combination of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and photoluminescence spectroscopy, along with first-principles calculations, was used to investigate the crystal structure and electronic properties. The optimal doping concentrations for Tb3+ and Ce3+ were determined to be 13% and 1%, respectively. Higher doping levels led to concentration quenching attributed to electric dipole–dipole interactions. Theoretical calculations confirmed that YPO4 possesses a direct bandgap of 5.88 eV. Energy transfer between Ce3+ and Tb3+ ions occurs primarily through an electric dipole–electric quadrupole mechanism, with a transfer efficiency reaching 50%. The co-doped YPO4:Tb3+,Ce3+ exhibited excellent thermal stability, highlighting its potential for applications in high-temperature fluorescence thermometry and fingerprint recognition. This work provides both theoretical insights and experimental support for advancing rare-earth-doped nanophosphors in anti-counterfeiting and biometric technologies.
{"title":"High Temperature Fluorescence Characteristics of YPO4: Tb3+,Ce3+ Nanophosphors and their Applications in Fingerprint Detection","authors":"Jinxiu Wu, Baolong Wu, Qianqian Zhang, Shengquan Wang, Zhaogang Liu, Yanhong Hu, Xiaowei Zhang, Dechao Li","doi":"10.1007/s13391-025-00613-4","DOIUrl":"10.1007/s13391-025-00613-4","url":null,"abstract":"<div><p>YPO<sub>4</sub> nanophosphors doped with Tb<sup>3+</sup>, Ce<sup>3+</sup>, and co-doped with Tb<sup>3+</sup>/Ce<sup>3+</sup> were synthesized via a hydrothermal method, and the effects of rare-earth doping on their structural and optical properties were comprehensively examined. A combination of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and photoluminescence spectroscopy, along with first-principles calculations, was used to investigate the crystal structure and electronic properties. The optimal doping concentrations for Tb<sup>3+</sup> and Ce<sup>3+</sup> were determined to be 13% and 1%, respectively. Higher doping levels led to concentration quenching attributed to electric dipole–dipole interactions. Theoretical calculations confirmed that YPO<sub>4</sub> possesses a direct bandgap of 5.88 eV. Energy transfer between Ce<sup>3+</sup> and Tb<sup>3+</sup> ions occurs primarily through an electric dipole–electric quadrupole mechanism, with a transfer efficiency reaching 50%. The co-doped YPO<sub>4</sub>:Tb<sup>3+</sup>,Ce<sup>3+</sup> exhibited excellent thermal stability, highlighting its potential for applications in high-temperature fluorescence thermometry and fingerprint recognition. This work provides both theoretical insights and experimental support for advancing rare-earth-doped nanophosphors in anti-counterfeiting and biometric technologies.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":536,"journal":{"name":"Electronic Materials Letters","volume":"22 2","pages":"166 - 178"},"PeriodicalIF":2.6,"publicationDate":"2025-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147340562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-15DOI: 10.1007/s13391-025-00600-9
In Hyeok Yeo, Yun Taek Park, Hee Jin Kim, Dong Ryul Lee, Sung Ho Lee, Seung Min Han
Fracture of SiNx layers within a semiconductor device can cause detrimental reliability issues, and measurement of fracture toughness is key in addressing this limitation. In this study, the fracture toughness of sputtered amorphous SiNx thin film was quantitatively evaluated using an energy-based nanoindentation method. Analysis of crack morphologies as a function of maximum indentation load revealed a sequential fracture process in 970 nm-thick SiNx film, consisting of delamination, buckling, and subsequent ring crack formation. The initiation of ring crack formation induced distinct pop-in event in the load–depth curves, which corresponded to an abrupt jump in the irreversible work ((:{W}_{irr}))–maximum load ((:{P}_{max})) plot. The energy released during ring crack formation was quantified from the difference in (:{W}_{irr}) with and without ring crack formation at identical maximum load. The calculated fracture toughness was in agreement with expectations with a value of (:6.83:MPasqrt{m}), which is indicative of high reliability of the energy-based method analysis. In contrast, the 94 nm-thick SiNx film exhibited no significant interfacial delamination under increasing indentation loads. Instead, radial crack propagation through film to substrate and irregular chippings were observed, highlighting the limitations of applying the energy-based method in such thin films. This work demonstrates both the applicability and the thickness-dependent limitations of the energy-based fracture toughness measurement for thin films, providing essential insights for optimizing process parameters to ensure reliability in semiconductor devices with thin coatings.
{"title":"Fracture Toughness Analysis of Sputtered SiNx Thin Films by Energy-Based Nanoindentation Method","authors":"In Hyeok Yeo, Yun Taek Park, Hee Jin Kim, Dong Ryul Lee, Sung Ho Lee, Seung Min Han","doi":"10.1007/s13391-025-00600-9","DOIUrl":"10.1007/s13391-025-00600-9","url":null,"abstract":"<div><p>Fracture of SiN<sub>x</sub> layers within a semiconductor device can cause detrimental reliability issues, and measurement of fracture toughness is key in addressing this limitation. In this study, the fracture toughness of sputtered amorphous SiN<sub>x</sub> thin film was quantitatively evaluated using an energy-based nanoindentation method. Analysis of crack morphologies as a function of maximum indentation load revealed a sequential fracture process in 970 nm-thick SiN<sub>x</sub> film, consisting of delamination, buckling, and subsequent ring crack formation. The initiation of ring crack formation induced distinct pop-in event in the load–depth curves, which corresponded to an abrupt jump in the irreversible work (<span>(:{W}_{irr})</span>)–maximum load (<span>(:{P}_{max})</span>) plot. The energy released during ring crack formation was quantified from the difference in <span>(:{W}_{irr})</span> with and without ring crack formation at identical maximum load. The calculated fracture toughness was in agreement with expectations with a value of <span>(:6.83:MPasqrt{m})</span>, which is indicative of high reliability of the energy-based method analysis. In contrast, the 94 nm-thick SiN<sub>x</sub> film exhibited no significant interfacial delamination under increasing indentation loads. Instead, radial crack propagation through film to substrate and irregular chippings were observed, highlighting the limitations of applying the energy-based method in such thin films. This work demonstrates both the applicability and the thickness-dependent limitations of the energy-based fracture toughness measurement for thin films, providing essential insights for optimizing process parameters to ensure reliability in semiconductor devices with thin coatings.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":536,"journal":{"name":"Electronic Materials Letters","volume":"22 1","pages":"92 - 101"},"PeriodicalIF":2.6,"publicationDate":"2025-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13391-025-00600-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-11DOI: 10.1007/s13391-025-00608-1
Kyusoon Pak, Yunseon Lee, Je Hyeong Kim, Minu Kim, Joo Yong Sim
We report a highly sensitive and durable fiber-type strain sensor (SCDC) fabricated via scalable dip-coating method using a styrene–isoprene–styrene (SIS)-modified multi-walled carbon nanotube (MWCNT) dispersion, stabilized with poly(3-dodecylthiophene) (P3DDT) to ensure uniform coating and prevent CNT aggregation. By optimizing the number of dip-coating cycles, five iterations were identified as ideal, resulting in a wide strain range of 54.7%, high linearity (R2 = 0.972), and a stable gauge factor of 6.69. The sensor demonstrates excellent mechanical durability, with a consistent resistance response after 1,000 cycles under 30% strain and a low hysteresis ratio of 13.76%. When integrated into a wearable sleeve, the sensor reliably captured elbow motion with clear signal differentiation. This simple yet effective dip-coating strategy enables seamless integration of strain sensors into textiles, maintaining mechanical compliance without additional post-processing—paving the way for practical, garment-embedded e-textile applications.
{"title":"Highly Sensitive and Robust Fiber Strain Sensor via Multiple Coating","authors":"Kyusoon Pak, Yunseon Lee, Je Hyeong Kim, Minu Kim, Joo Yong Sim","doi":"10.1007/s13391-025-00608-1","DOIUrl":"10.1007/s13391-025-00608-1","url":null,"abstract":"<div><p>We report a highly sensitive and durable fiber-type strain sensor (SCDC) fabricated via scalable dip-coating method using a styrene–isoprene–styrene (SIS)-modified multi-walled carbon nanotube (MWCNT) dispersion, stabilized with poly(3-dodecylthiophene) (P3DDT) to ensure uniform coating and prevent CNT aggregation. By optimizing the number of dip-coating cycles, five iterations were identified as ideal, resulting in a wide strain range of 54.7%, high linearity (R<sup>2</sup> = 0.972), and a stable gauge factor of 6.69. The sensor demonstrates excellent mechanical durability, with a consistent resistance response after 1,000 cycles under 30% strain and a low hysteresis ratio of 13.76%. When integrated into a wearable sleeve, the sensor reliably captured elbow motion with clear signal differentiation. This simple yet effective dip-coating strategy enables seamless integration of strain sensors into textiles, maintaining mechanical compliance without additional post-processing—paving the way for practical, garment-embedded e-textile applications.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":536,"journal":{"name":"Electronic Materials Letters","volume":"22 2","pages":"114 - 121"},"PeriodicalIF":2.6,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147338259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-08DOI: 10.1007/s13391-025-00611-6
Sung Yeol Choi, Chaeheon Woo, Da Woon Wang, Hyeon-Seok Bang, Dong Ki Lee, Hyung-Suk Oh, Kyong-Hwan Kim, Jae-Young Choi, Hye-Kyong Choi, Jeong Min Baik
The electrochemical reduction of CO2 (CO2RR) provides a promising approach to mitigate greenhouse gas emissions while generating value-added chemicals. Among potential products, C2 species such as ethanol and ethylene are particularly attractive, yet achieving their selective and stable formation remains a major challenge. In this study, we compare two Cu–carbon catalyst synthesis strategies, i.e., chemical exfoliation–reduction (CER) based on a high-temperature acid treatment and hydrothermal (HT) synthesis based on a mild bottom-up method. Structural and electrochemical analyses revealed that HT produces atomically dispersed Cu–N active sites with enhanced selectivity toward ethanol and ethylene (ethanol Faraday efficiency ~ 38% at − 0.4 V, with HER suppressed below 30%), whereas CER yields heterogeneous CuOx clusters that mainly generate C1 products with high H2 output. The C2 Faradaic efficiency remained above 30% within the potential range of −0.5 to 0.9 V in 1.0 M KOH electrolyte condition. Beyond catalytic activity, an integrated techno-economic, life-cycle, and social life-cycle (3E) assessment demonstrated that HT offered lower synthesis cost, reduced environmental impact, and greater user acceptance. Collectively, these results establish HT as a more efficient and sustainable pathway for CO2RR catalyst development and highlight the value of coupling electrochemical evaluation with holistic 3E analysis to guide technologies that align performance, sustainability, and social acceptance.
Graphical abstract
电化学还原CO2 （CO2RR）为减少温室气体排放，同时产生增值化学品提供了一种有前途的方法。在潜在的产物中，C2物种如乙醇和乙烯特别有吸引力，但实现它们的选择性和稳定形成仍然是一个主要挑战。在本研究中，我们比较了两种铜碳催化剂的合成策略，即基于高温酸处理的化学剥离-还原（CER）和基于温和的自下而上方法的水热（HT）合成。结构和电化学分析表明，高温反应产生原子分散的Cu-N活性位点，对乙醇和乙烯的选择性增强（在−0.4 V时乙醇法拉第效率为38%，HER被抑制在30%以下），而高温反应产生异相CuOx簇，主要生成C1产物，H2产量高。在−0.5 ~ 0.9 V电势范围内，在1.0 M KOH电解液条件下，C2法拉第效率保持在30%以上。除了催化活性之外，综合技术经济、生命周期和社会生命周期（3E）评估表明，高温处理具有更低的合成成本、更小的环境影响和更高的用户接受度。总的来说，这些结果确立了HT是一种更有效、更可持续的CO2RR催化剂开发途径，并突出了电化学评价与整体3E分析相结合的价值，以指导协调性能、可持续性和社会接受度的技术。图形抽象
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Pub Date : 2025-11-07DOI: 10.1007/s13391-025-00614-3
Jaehyung Park, Jiwan Kim
This study demonstrates the use of 2,2′,2′′-(1,3,5-benzenetriyl)-tris(1-phenyl-1 H-benzimidazole) (TPBi) as a stabilizing interlayer beneath the Ag top electrode in top-emitting quantum dot light-emitting diodes (QLEDs). The TPBi layer effectively suppresses Ag agglomeration during thermal evaporation, thereby improving film uniformity and optical transmittance from 41.9 to 44.4%. This morphological enhancement yields superior device performance, with the resulting QLEDs based on CdZnSeS/ZnS QDs achieving a peak luminance of 118,110 cd/m² and a current efficiency of 39.3 cd/A. The highest efficiency is obtained at the current density corresponding to peak luminance, which is highly advantageous for practical displays. This work highlights a new functional role of TPBi beyond charge transport and presents an effective strategy to enhance the device performance and fabrication reliability of top-emitting QLEDs for advanced display technologies.
Graphical Abstract
本研究证明了在顶发射量子点发光二极管（qled）中使用2,2 ',2 " -（1,3,5-苯三基）-三（1-苯基-1 h -苯并咪唑）（TPBi）作为银顶电极下的稳定中间层。TPBi层有效抑制了热蒸发过程中银的团聚，提高了薄膜的均匀性，光学透过率从41.9提高到44.4%。这种形态增强产生了优异的器件性能，基于CdZnSeS/ZnS QDs的qled达到了118,110 cd/m²的峰值亮度和39.3 cd/ a的电流效率。在峰值亮度对应的电流密度下获得最高的效率，这对实际显示非常有利。这项工作强调了TPBi在电荷传输之外的新功能作用，并提出了一种有效的策略来提高用于先进显示技术的顶发射qled的器件性能和制造可靠性。图形抽象
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