Pub Date : 2024-11-19DOI: 10.1016/j.mssp.2024.109120
M.Y. Raïâ, R. Masrour, M. Hamedoun, J. Kharbach, A. Rezzouk, N. Benzakour, K. Bouslykhane
The study investigates the CoTiFeGe quaternary Heusler alloy, focusing on its bulk structure with various ordering types and its (001) surface terminations of ∗CoFe and ∗TiGe. Employing density functional theory (DFT), researchers analyzed the material's properties. Calculations of elastic constants provided insights into the alloy's mechanical properties. Electronic structure analysis, specifically the density of states and band structure for XA-type ordering, revealed half-metallic characteristics. Using both GGA and mBJ-GGA methods, the study found band gaps of 0.490 eV and 0.982 eV, respectively, confirming the alloy's half-metallic nature. Surface analysis showed that the ∗CoFe-terminated (001) surface loses its half-metallic ferromagnetic character, while the ∗TiGe-terminated surface maintains complete spin polarization. This finding has significant implications for potential spintronic applications. Optical property investigations of both bulk and (001) surfaces supported the material's semiconducting nature. The primary optical reflections were observed in the visible and infrared regions, with minimal loss in the same spectral range. The presence of absorption in the (001) surface suggests potential applications in optoelectronics. Additionally, the research explored the alloy's thermoelectric properties by examining its transport coefficients.
{"title":"Comprehensive analysis of bulk and (001) surface properties of the quaternary Heusler compound CoTiFeGe","authors":"M.Y. Raïâ, R. Masrour, M. Hamedoun, J. Kharbach, A. Rezzouk, N. Benzakour, K. Bouslykhane","doi":"10.1016/j.mssp.2024.109120","DOIUrl":"10.1016/j.mssp.2024.109120","url":null,"abstract":"<div><div>The study investigates the CoTiFeGe quaternary Heusler alloy, focusing on its bulk structure with various ordering types and its (001) surface terminations of ∗CoFe and ∗TiGe. Employing density functional theory (DFT), researchers analyzed the material's properties. Calculations of elastic constants provided insights into the alloy's mechanical properties. Electronic structure analysis, specifically the density of states and band structure for XA-type ordering, revealed half-metallic characteristics. Using both GGA and mBJ-GGA methods, the study found band gaps of 0.490 eV and 0.982 eV, respectively, confirming the alloy's half-metallic nature. Surface analysis showed that the ∗CoFe-terminated (001) surface loses its half-metallic ferromagnetic character, while the ∗TiGe-terminated surface maintains complete spin polarization. This finding has significant implications for potential spintronic applications. Optical property investigations of both bulk and (001) surfaces supported the material's semiconducting nature. The primary optical reflections were observed in the visible and infrared regions, with minimal loss in the same spectral range. The presence of absorption in the (001) surface suggests potential applications in optoelectronics. Additionally, the research explored the alloy's thermoelectric properties by examining its transport coefficients.</div></div>","PeriodicalId":18240,"journal":{"name":"Materials Science in Semiconductor Processing","volume":"187 ","pages":"Article 109120"},"PeriodicalIF":4.2,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142706011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This research delves into the photocatalytic degradation of phenol using CeO2 nanoparticles synthesized through solution combustion synthesis (SCS) at varying calcination temperatures (250, 300, 400, 500, and 600 °C). A comprehensive array of characterization techniques was employed, including XRD, FTIR, SEM-EDS, HR-TEM, N2 physisorption, UV–Vis DRS, Raman spectroscopy, and XPS. Our findings reveal a profound influence of calcination temperatures on the presence and quantity of Ce3+ and Ce4+ species, thereby modulating defective sites and surface area, crucial factors impacting performance. CeO2 synthesized at 400 °C stands out with a notable combination of high defects, extensive surface area, and a photocatalytic efficiency of 62 %. This work enhances our understanding of CeO2 photocatalysts for environmental applications and emphasizes the superior performance of mild calcination temperatures in ceria materials.
{"title":"Effect of calcination temperature on CeO2-based catalysts with enhanced photocatalytic degradation of phenol under UV light","authors":"L.A. Ramos-Huerta , Octavio Aguilar-Martínez , Yanet Piña-Pérez , Víctor Santes , Luis Lartundo Rojas , Francisco Tzompantzi , C.E. Santolalla-Vargas","doi":"10.1016/j.mssp.2024.109123","DOIUrl":"10.1016/j.mssp.2024.109123","url":null,"abstract":"<div><div>This research delves into the photocatalytic degradation of phenol using CeO<sub>2</sub> nanoparticles synthesized through solution combustion synthesis (SCS) at varying calcination temperatures (250, 300, 400, 500, and 600 °C). A comprehensive array of characterization techniques was employed, including XRD, FTIR, SEM-EDS, HR-TEM, N<sub>2</sub> physisorption, UV–Vis DRS, Raman spectroscopy, and XPS. Our findings reveal a profound influence of calcination temperatures on the presence and quantity of Ce<sup>3+</sup> and Ce<sup>4+</sup> species, thereby modulating defective sites and surface area, crucial factors impacting performance. CeO<sub>2</sub> synthesized at 400 °C stands out with a notable combination of high defects, extensive surface area, and a photocatalytic efficiency of 62 %. This work enhances our understanding of CeO<sub>2</sub> photocatalysts for environmental applications and emphasizes the superior performance of mild calcination temperatures in ceria materials.</div></div>","PeriodicalId":18240,"journal":{"name":"Materials Science in Semiconductor Processing","volume":"187 ","pages":"Article 109123"},"PeriodicalIF":4.2,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142706009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-17DOI: 10.1016/j.mssp.2024.109127
Sanling Fu , Menghao Yin , Gaojie Li
In recent years, metal oxide semiconductor nanomaterials have been found important applications in the detection of volatile organic compounds (VOCs) due to their excellent gas-sensing properties. In this study, Co3O4-ZnO porous hierarchical heterostructure nanomaterial was synthesised via the facile hydrothermal route. The sensors prepared from pristine ZnO and Co3O4-ZnO composites exhibited excellent triethylamine sensing properties. The response value of pristine ZnO to 50 ppm triethylamine was 178 at 300 °C, while the response value of Co0.5 sensor reached 2036 under the same condition, and the response value of Co0.5 sensor was 2.6 in a 500 ppb triethylamine atmosphere. Meanwhile, the selectivity of Co3O4-ZnO sample was also significantly improved compared with pristine ZnO, and the obtained sensors had excellent repeatability and long-term stability. Therefore, the Co3O4-ZnO sensor in this work had potential applications in practicable triethylamine detection. Such an exceptional triethylamine sensing performance could be sourced from its unique porous hierarchical structure and the catalytic effect of the introduced Co3O4 on the surface reaction, as well as the synergistic effect of ZnO and Co3O4.
{"title":"Ultra-high response and excellent selectivity of triethylamine gas sensor based on Co3O4-ZnO porous hierarchical heterostructure","authors":"Sanling Fu , Menghao Yin , Gaojie Li","doi":"10.1016/j.mssp.2024.109127","DOIUrl":"10.1016/j.mssp.2024.109127","url":null,"abstract":"<div><div>In recent years, metal oxide semiconductor nanomaterials have been found important applications in the detection of volatile organic compounds (VOCs) due to their excellent gas-sensing properties. In this study, Co<sub>3</sub>O<sub>4</sub>-ZnO porous hierarchical heterostructure nanomaterial was synthesised via the facile hydrothermal route. The sensors prepared from pristine ZnO and Co<sub>3</sub>O<sub>4</sub>-ZnO composites exhibited excellent triethylamine sensing properties. The response value of pristine ZnO to 50 ppm triethylamine was 178 at 300 °C, while the response value of Co0.5 sensor reached 2036 under the same condition, and the response value of Co0.5 sensor was 2.6 in a 500 ppb triethylamine atmosphere. Meanwhile, the selectivity of Co<sub>3</sub>O<sub>4</sub>-ZnO sample was also significantly improved compared with pristine ZnO, and the obtained sensors had excellent repeatability and long-term stability. Therefore, the Co<sub>3</sub>O<sub>4</sub>-ZnO sensor in this work had potential applications in practicable triethylamine detection. Such an exceptional triethylamine sensing performance could be sourced from its unique porous hierarchical structure and the catalytic effect of the introduced Co<sub>3</sub>O<sub>4</sub> on the surface reaction, as well as the synergistic effect of ZnO and Co<sub>3</sub>O<sub>4</sub>.</div></div>","PeriodicalId":18240,"journal":{"name":"Materials Science in Semiconductor Processing","volume":"187 ","pages":"Article 109127"},"PeriodicalIF":4.2,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142662300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-17DOI: 10.1016/j.mssp.2024.109101
M. Leo Edward , M. Roselin Ranjitha , G. Thennarasu , E. Ranjith Kumar , A.F. Abd El-Rehim , V. Jaisankar
We propose a novel solid-state composite polymer electrolyte (CPE) that includes Li7La2.5Ce0.5Zr2O12 (Ce-LLZO), chitosan (CS)/agar-agar (AA) polymer, polyethylene glycol (PEG) plasticizer, and LiClO4 salt. At 25 °C, the CPE3 formulation, consisting of 15 wt% Ce-LLZO, 60 wt% CS-AA, 15 wt% PEG, and 10 wt% LiClO4, demonstrated exceptional lithium (Li)-ion conductivity of 5.18 × 10-3 S cm−1 and an optimal transference number (TLi+) of 0.937. We assessed the electrochemical stability of CPE3 using linear sweep voltammetry, which revealed a maximum stability limit of 4.1 V (versus Li/Li+). In addition, the coin cell made with the Li||CPE3||NMC configuration had an amazing discharge capacity of 163 mAhg-1 and stayed stable for up to 100 cycles at 0.1 °C in room temperature. Conversely, when subjected to Li-plating/stripping cycles, the symmetric Li||CPE3||Li cell exhibited stability for 550 h and maintained a current density of 2.0 mA cm−2. Compared to Li-metal, the proposed material exhibited reduced overpotential while simultaneously enhancing electrochemical stability.
{"title":"A high-performance flexible biopolymer-based Ce oxide composite electrolyte for lithium-ion battery dendrite reduction","authors":"M. Leo Edward , M. Roselin Ranjitha , G. Thennarasu , E. Ranjith Kumar , A.F. Abd El-Rehim , V. Jaisankar","doi":"10.1016/j.mssp.2024.109101","DOIUrl":"10.1016/j.mssp.2024.109101","url":null,"abstract":"<div><div>We propose a novel solid-state composite polymer electrolyte (CPE) that includes Li<sub>7</sub>La<sub>2.5</sub>Ce<sub>0.5</sub>Zr<sub>2</sub>O<sub>12</sub> (Ce-LLZO), chitosan (CS)/agar-agar (AA) polymer, polyethylene glycol (PEG) plasticizer, and LiClO<sub>4</sub> salt. At 25 °C, the CPE<sub>3</sub> formulation, consisting of 15 wt% Ce-LLZO, 60 wt% CS-AA, 15 wt% PEG, and 10 wt% LiClO<sub>4</sub>, demonstrated exceptional lithium (Li)-ion conductivity of 5.18 × 10<sup>-3</sup> S cm<sup>−1</sup> and an optimal transference number (TLi<sup>+</sup>) of 0.937. We assessed the electrochemical stability of CPE<sub>3</sub> using linear sweep voltammetry, which revealed a maximum stability limit of 4.1 V (versus Li/Li+). In addition, the coin cell made with the Li||CPE<sub>3</sub>||NMC configuration had an amazing discharge capacity of 163 mAhg-1 and stayed stable for up to 100 cycles at 0.1 °C in room temperature. Conversely, when subjected to Li-plating/stripping cycles, the symmetric Li||CPE<sub>3</sub>||Li cell exhibited stability for 550 h and maintained a current density of 2.0 mA cm<sup>−2</sup>. Compared to Li-metal, the proposed material exhibited reduced overpotential while simultaneously enhancing electrochemical stability.</div></div>","PeriodicalId":18240,"journal":{"name":"Materials Science in Semiconductor Processing","volume":"187 ","pages":"Article 109101"},"PeriodicalIF":4.2,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142662299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-16DOI: 10.1016/j.mssp.2024.109109
Pranti Saha , In Jun Park , Protik Das , Fariborz Kargar
We have investigated the structural, mechanical, electronic and optical properties of Rb-based cubic perovskite RbBaX (X = F, Cl, Br, I) under hydrostatic pressure, using first-principle density functional theory (DFT). All RbBaX perovskites exhibit thermodynamic and mechanical stability at ambient pressure. RbBaF remains structurally stable across all examined pressures, while RbBaCl, RbBaBr, and RbBaI maintain mechanical stability up to 60, 60, and 40 GPa, respectively. These materials are ductile even at elevated pressure. RbBaF has a direct bandgap of 4.80 eV while other compositions exhibit indirect band gaps of 4.37, 3.73, and 3.24 eV with halide atoms of Cl, Br, and I, respectively. Under elevated hydrostatic pressure, only RbBaCl and RbBaI exhibit an indirect-to-direct band transition while others preserve their nature of band gap. Our results show that spin–orbit coupling significantly affects only the valance bands of larger-sized halides (Cl, Br, I). With hybrid functional (HSE) correction, the band gaps of these four materials increase to 6.7, 5.6, 4.8 and 4.4 eV, respectively, but the nature of direct/indirect band transition remains unchanged. Orbital-decomposed partial density of states calculation reveals that the halogen p-orbitals dominate the valence band near the Fermi level, while Rb 5s-orbital affects the conduction band minima the most. Investigation of the optical properties reveals wide-band absorption, low electron loss, moderate reflectivity and lower refractive index in the UV to deep-UV range. The strength and range of absorption increases significantly with hydrostatic pressure, suggesting that RbBaX perovskites are promising candidates for tunable UV-absorbing optoelectronic devices.
{"title":"First-principles study of structural, electronic and optical properties of non-toxic RbBaX3 (X = F, Cl, Br, I) perovskites under hydrostatic pressure","authors":"Pranti Saha , In Jun Park , Protik Das , Fariborz Kargar","doi":"10.1016/j.mssp.2024.109109","DOIUrl":"10.1016/j.mssp.2024.109109","url":null,"abstract":"<div><div>We have investigated the structural, mechanical, electronic and optical properties of Rb-based cubic perovskite RbBaX<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> (X = F, Cl, Br, I) under hydrostatic pressure, using first-principle density functional theory (DFT). All RbBaX<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> perovskites exhibit thermodynamic and mechanical stability at ambient pressure. RbBaF<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> remains structurally stable across all examined pressures, while RbBaCl<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>, RbBaBr<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>, and RbBaI<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> maintain mechanical stability up to 60, 60, and 40 GPa, respectively. These materials are ductile even at elevated pressure. RbBaF<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> has a direct bandgap of 4.80 eV while other compositions exhibit indirect band gaps of 4.37, 3.73, and 3.24 eV with halide atoms of Cl, Br, and I, respectively. Under elevated hydrostatic pressure, only RbBaCl<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> and RbBaI<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> exhibit an indirect-to-direct band transition while others preserve their nature of band gap. Our results show that spin–orbit coupling significantly affects only the valance bands of larger-sized halides (Cl, Br, I). With hybrid functional (HSE) correction, the band gaps of these four materials increase to 6.7, 5.6, 4.8 and 4.4 eV, respectively, but the nature of direct/indirect band transition remains unchanged. Orbital-decomposed partial density of states calculation reveals that the halogen <em>p</em>-orbitals dominate the valence band near the Fermi level, while Rb 5<em>s</em>-orbital affects the conduction band minima the most. Investigation of the optical properties reveals wide-band absorption, low electron loss, moderate reflectivity and lower refractive index in the UV to deep-UV range. The strength and range of absorption increases significantly with hydrostatic pressure, suggesting that RbBaX<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> perovskites are promising candidates for tunable UV-absorbing optoelectronic devices.</div></div>","PeriodicalId":18240,"journal":{"name":"Materials Science in Semiconductor Processing","volume":"187 ","pages":"Article 109109"},"PeriodicalIF":4.2,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, we have investigated the structural, electronic, mechanical, and optical properties of ZnSbF3-I and ZnSbF3-II by altering the position of Zn and Sb through density functional theory (DFT) for the first time. The structural stability of both structures was confirmed by calculating formation enthalpy. A remarkable phenomenon has been observed from the electronic band structures analysis, whenever altering the atomic of Zn and Sb, which leads to a transition from semiconducting, ZnSbF3-I to metallic, ZnSbF3-II conductivity. The obtained bandgap value of ZnSbF3-I is of the order of 0.97 eV with indirect transition and the spin-orbit coupling (SOC) effect reduced the band gap energy to 0.49 eV. Density of states (DOS) curves revealed that the Sb-5p state is mainly responsible for this phase transition. The estimated elastic constants suggested that both phases are mechanically stable. By assessing the different elastic parameters, it can be concluded that both phases are mechanically ductile, machinable, isotropic, and soft in nature. A large value of bulk modulus for ZnSbF3-II indicates that it is harder and cannot be compressed as easily as ZnSbF3-I. The structures exhibit high efficiency in absorbing UV light. ZnSbF3-II's strong reflectivity in the infrared spectrum makes it an option to use for IR shielding. This study will guide further theoretical and experimental investigation.
{"title":"Atomic position dependent structural, electronic, mechanical and optical properties of ZnSbF3 fluoroperovskites","authors":"Tanmoy Kumar Ghosh , M.N.H. Liton , Arpon Chakraborty , M.K.R. Khan , M.S.I. Sarker","doi":"10.1016/j.mssp.2024.109065","DOIUrl":"10.1016/j.mssp.2024.109065","url":null,"abstract":"<div><div>In this study, we have investigated the structural, electronic, mechanical, and optical properties of ZnSbF<sub>3</sub>-I and ZnSbF<sub>3</sub>-II by altering the position of Zn and Sb through density functional theory (DFT) for the first time. The structural stability of both structures was confirmed by calculating formation enthalpy. A remarkable phenomenon has been observed from the electronic band structures analysis, whenever altering the atomic of Zn and Sb, which leads to a transition from semiconducting, ZnSbF<sub>3</sub>-I to metallic, ZnSbF<sub>3</sub>-II conductivity. The obtained bandgap value of ZnSbF<sub>3</sub>-I is of the order of 0.97 eV with indirect transition and the spin-orbit coupling (SOC) effect reduced the band gap energy to 0.49 eV. Density of states (DOS) curves revealed that the Sb-<em>5p</em> state is mainly responsible for this phase transition. The estimated elastic constants suggested that both phases are mechanically stable. By assessing the different elastic parameters, it can be concluded that both phases are mechanically ductile, machinable, isotropic, and soft in nature. A large value of bulk modulus for ZnSbF<sub>3</sub>-II indicates that it is harder and cannot be compressed as easily as ZnSbF<sub>3</sub>-I. The structures exhibit high efficiency in absorbing UV light. ZnSbF<sub>3</sub>-II's strong reflectivity in the infrared spectrum makes it an option to use for IR shielding. This study will guide further theoretical and experimental investigation.</div></div>","PeriodicalId":18240,"journal":{"name":"Materials Science in Semiconductor Processing","volume":"187 ","pages":"Article 109065"},"PeriodicalIF":4.2,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-15DOI: 10.1016/j.mssp.2024.109118
Hoang-Tien Cao, Jeng-Rong Ho, Pi-Cheng Tung, Hai-Ping Tsui, Chih-Kuang Lin
Semi-conductive silicon carbide (semi-SiC) wafers are essential in the semiconductor industry, but their high hardness and brittleness make traditional machining difficult. Electric discharge machining (EDM) is an alternative method for machining semi-SiC wafer. This study investigates the effects of discharge energy parameters, such as pulse-on time and peak current, on the surface and subsurface characteristics of semi-SiC wafers subjected to micro-EDM drilling. The machined surface and subsurface morphology and microstructure were characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). SEM micrographs revealed the presence of craters, resolidified material, cracks, and micro-pores on the machined surface, influenced by the thermal energy generated during the EDM process. The material removal mechanisms identified include melting, vaporization, spalling, and oxidation. EDS analyses indicated a larger discharge energy led to an increase in carbon and oxygen concentrations on the machined surfaces, likely due to the decomposition of SiC and oxidation during EDM. XPS analysis identified the presence of graphite, SiO2, Cu particles, Cu2O, and CuO on the machined surface. TEM micrographs revealed three distinct regions in the subsurface, namely a recast layer, a heat-affected zone (HAZ), and the unaffected bulk SiC. These layers exhibited different microstructures, with the thickness of the recast layer and HAZ being dependent on the discharge energy. This study highlights the advantages of micro-EDM over other techniques, achieving a thin recast layer and minimal HAZ, thereby preserving the surface and subsurface integrity of the semi-SiC wafer.
半导电碳化硅（semi-SiC）晶片是半导体工业中不可或缺的材料，但由于其硬度高、脆性大，传统的加工方法很难加工。放电加工（EDM）是加工半碳化硅晶片的一种替代方法。本研究探讨了脉冲接通时间和峰值电流等放电能量参数对微电火花钻孔加工半 SiC 晶圆表面和亚表面特性的影响。使用扫描电子显微镜 (SEM)、能量色散 X 射线光谱 (EDS)、X 射线光电子能谱 (XPS) 和透射电子显微镜 (TEM) 对加工表面和次表面形态及微观结构进行了表征。扫描电镜显微照片显示，受电火花加工过程中产生的热能影响，加工表面出现了凹坑、分解材料、裂纹和微孔。材料去除机制包括熔化、汽化、剥落和氧化。EDS 分析表明，放电能量越大，加工表面的碳和氧浓度就越高，这可能是由于电火花加工过程中碳化硅的分解和氧化作用造成的。XPS 分析确定了加工表面存在石墨、SiO2、铜颗粒、Cu2O 和 CuO。TEM 显微照片显示了次表面的三个不同区域，即再铸层、热影响区 (HAZ) 和未受影响的整体 SiC。这些层表现出不同的微观结构，重铸层和热影响区的厚度取决于放电能量。与其他技术相比，这项研究凸显了微型放电加工的优势，即可以获得较薄的再铸层和最小的热影响区，从而保持半碳化硅晶片表面和次表面的完整性。
{"title":"Characterization of machined surface in semi-conductive SiC wafer subjected to micro-EDM drilling","authors":"Hoang-Tien Cao, Jeng-Rong Ho, Pi-Cheng Tung, Hai-Ping Tsui, Chih-Kuang Lin","doi":"10.1016/j.mssp.2024.109118","DOIUrl":"10.1016/j.mssp.2024.109118","url":null,"abstract":"<div><div>Semi-conductive silicon carbide (semi-SiC) wafers are essential in the semiconductor industry, but their high hardness and brittleness make traditional machining difficult. Electric discharge machining (EDM) is an alternative method for machining semi-SiC wafer. This study investigates the effects of discharge energy parameters, such as pulse-on time and peak current, on the surface and subsurface characteristics of semi-SiC wafers subjected to micro-EDM drilling. The machined surface and subsurface morphology and microstructure were characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). SEM micrographs revealed the presence of craters, resolidified material, cracks, and micro-pores on the machined surface, influenced by the thermal energy generated during the EDM process. The material removal mechanisms identified include melting, vaporization, spalling, and oxidation. EDS analyses indicated a larger discharge energy led to an increase in carbon and oxygen concentrations on the machined surfaces, likely due to the decomposition of SiC and oxidation during EDM. XPS analysis identified the presence of graphite, SiO<sub>2</sub>, Cu particles, Cu<sub>2</sub>O, and CuO on the machined surface. TEM micrographs revealed three distinct regions in the subsurface, namely a recast layer, a heat-affected zone (HAZ), and the unaffected bulk SiC. These layers exhibited different microstructures, with the thickness of the recast layer and HAZ being dependent on the discharge energy. This study highlights the advantages of micro-EDM over other techniques, achieving a thin recast layer and minimal HAZ, thereby preserving the surface and subsurface integrity of the semi-SiC wafer.</div></div>","PeriodicalId":18240,"journal":{"name":"Materials Science in Semiconductor Processing","volume":"187 ","pages":"Article 109118"},"PeriodicalIF":4.2,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Inducing post-transition metals in an oxide semiconductor system has a high potential for use in storage for neuromorphic computing. It is challenging to find a material that can be switched stably between multiple resistance states. This research explores the memristive properties of Sn (post-transition metal)-doped ZnO (SZO) thin films, emphasizing their application in memristor devices. The (magnetron sputtered) synthesized SZO thin films in the form of Ag/SZO/Au/Ti/SiO₂ device demonstrated a clear bipolar resistive switching (BRS) behavior with VSET and VRESET of 1.0 V and −0.75 V, respectively. The memristor could change between a high resistance state and a low resistance state with a high RON/OFF rate of 104, mimicking synaptic behaviors such as potentiation and depression. This switching is attributed to the formation and dissolution of Ag filaments within the SZO layer, influenced by the migration of Ag⁺ ions and the presence of oxygen vacancies. These vacancies facilitate the formation of conductive filaments under positive bias and their dissolution under negative bias. The endurance and retention tests showed stable switching characteristics, with the memristor maintaining distinct HRS and LRS over 100 cycles and retaining these states for over 5K seconds without significant degradation. Finally, the nonlinearity values for potentiation and depression were αp∼1.6 and αd ∼ -0.14, suggesting that the memristor may be more responsive to increasing synaptic weights in biological systems. The linearity response at a very small pulse width showed the device is more applicable for neuromorphic applications. The observed memristor combined with stable endurance and retention performance, suggests that this memristor structure could play a crucial role in the development of artificial synapses and memory technologies.
{"title":"Nonlinear and linear conductance modulation and synaptic plasticity in stable tin-zinc oxide based-memristor for neuro-inspired computing","authors":"Rajwali Khan , Shahid Iqbal , Fazal Raziq , Pardha Saradhi Maram , Sabyasachi Chakrabortty , Sambasivam Sangaraju","doi":"10.1016/j.mssp.2024.109111","DOIUrl":"10.1016/j.mssp.2024.109111","url":null,"abstract":"<div><div>Inducing post-transition metals in an oxide semiconductor system has a high potential for use in storage for neuromorphic computing. It is challenging to find a material that can be switched stably between multiple resistance states. This research explores the memristive properties of Sn (post-transition metal)-doped ZnO (SZO) thin films, emphasizing their application in memristor devices. The (magnetron sputtered) synthesized SZO thin films in the form of Ag/SZO/Au/Ti/SiO₂ device demonstrated a clear bipolar resistive switching (BRS) behavior with V<sub>SET</sub> and V<sub>RESET</sub> of 1.0 V and −0.75 V, respectively. The memristor could change between a high resistance state and a low resistance state with a high R<sub>ON/OFF</sub> rate of 10<sup>4</sup>, mimicking synaptic behaviors such as potentiation and depression. This switching is attributed to the formation and dissolution of Ag filaments within the SZO layer, influenced by the migration of Ag⁺ ions and the presence of oxygen vacancies. These vacancies facilitate the formation of conductive filaments under positive bias and their dissolution under negative bias. The endurance and retention tests showed stable switching characteristics, with the memristor maintaining distinct HRS and LRS over 100 cycles and retaining these states for over 5K seconds without significant degradation. Finally, the nonlinearity values for potentiation and depression were α<sub>p</sub>∼1.6 and α<sub>d</sub> ∼ -0.14, suggesting that the memristor may be more responsive to increasing synaptic weights in biological systems. The linearity response at a very small pulse width showed the device is more applicable for neuromorphic applications. The observed memristor combined with stable endurance and retention performance, suggests that this memristor structure could play a crucial role in the development of artificial synapses and memory technologies.</div></div>","PeriodicalId":18240,"journal":{"name":"Materials Science in Semiconductor Processing","volume":"186 ","pages":"Article 109111"},"PeriodicalIF":4.2,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-15DOI: 10.1016/j.mssp.2024.109116
Nabeel Israr , Muhammad Awais Jehangir , Ammar M. Tighezza , Shamim Khan , G. Murtaza , Muhammad Saeed
Perovskites systems are leading the photovoltaic technology now a days. For the consistent renewable energy applications new materials required with the desirable properties. In this work six new materials are being predicted which may be very useful for the renewable energy applications. The full potential scheme of linearized augmented plane wave with the local orbitals is used for the calculations with the PBEsol GGA and mBJ potentials for the exchange-correlation effects. The structural and elastic parameters of A2BAuI6 (A = K or Rb or Cs, B = Sc or Y) are computed, and the responses exhibits that such compounds are stable, have a ductile nature, and are described by a high elastic anisotropy. The bandgaps were identified via the electrical band structure computations for A2BAuI6 (A = K, Rb, Cs; B = Sc or Y) compounds as 1.25 eV, 1.64 eV, 1.24 eV, 1.62 eV, 1.25 eV and 2.04 eV with TB-mBJ + SOC approach. The calculated compounds have much dispersion in their bands and minimal carrier effective mass. Lattice thermal conductivity () is computed via Slack's equation for all computed compounds are 0.29 × 1014 W/mK, 0.31 × 1014 W/mK, 0.29 × 1014 W/mK, 0.31 × 1014 W/mK, 0.39 × 1014 W/mK and 0.29 × 1014 W/mK, indicating a promising future for thermoelectric uses. The calculation of thermoelectric parameters, including the power factor, Seebeck coefficient, and figure of merit, serves another prospective purpose and confirms the potential high use of these materials in thermoelectric devices. Likewise, acceptable quality characteristics like long diffusion length, tunable band-gap, high mobility, am-bipolar charge transport, and high absorption reinforce these compounds which make them even more suitable for photovoltaic applications.
{"title":"The effect of PBEsol GGA and mBJ potentials on the structural, electronic, optical, elastic and thermoelectric properties of A2BAuI6 (A = K or Rb or Cs, B = Sc or Y)","authors":"Nabeel Israr , Muhammad Awais Jehangir , Ammar M. Tighezza , Shamim Khan , G. Murtaza , Muhammad Saeed","doi":"10.1016/j.mssp.2024.109116","DOIUrl":"10.1016/j.mssp.2024.109116","url":null,"abstract":"<div><div>Perovskites systems are leading the photovoltaic technology now a days. For the consistent renewable energy applications new materials required with the desirable properties. In this work six new materials are being predicted which may be very useful for the renewable energy applications. The full potential scheme of linearized augmented plane wave with the local orbitals is used for the calculations with the PBEsol GGA and mBJ potentials for the exchange-correlation effects. The structural and elastic parameters of A<sub>2</sub>BAuI<sub>6</sub> (A = K or Rb or Cs, B = Sc or Y) are computed, and the responses exhibits that such compounds are stable, have a ductile nature, and are described by a high elastic anisotropy. The bandgaps were identified via the electrical band structure computations for A<sub>2</sub>BAuI<sub>6</sub> (A = K, Rb, Cs; B = Sc or Y) compounds as 1.25 eV, 1.64 eV, 1.24 eV, 1.62 eV, 1.25 eV and 2.04 eV with TB-mBJ + SOC approach. The calculated compounds have much dispersion in their bands and minimal carrier effective mass. Lattice thermal conductivity (<span><math><mrow><msub><mi>K</mi><mi>L</mi></msub></mrow></math></span>) is computed via Slack's equation for all computed compounds are 0.29 × 10<sup>14</sup> W/mK, 0.31 × 10<sup>14</sup> W/mK, 0.29 × 10<sup>14</sup> W/mK, 0.31 × 10<sup>14</sup> W/mK, 0.39 × 10<sup>14</sup> W/mK and 0.29 × 10<sup>14</sup> W/mK, indicating a promising future for thermoelectric uses. The calculation of thermoelectric parameters, including the power factor, Seebeck coefficient, and figure of merit, serves another prospective purpose and confirms the potential high use of these materials in thermoelectric devices. Likewise, acceptable quality characteristics like long diffusion length, tunable band-gap, high mobility, am-bipolar charge transport, and high absorption reinforce these compounds which make them even more suitable for photovoltaic applications.</div></div>","PeriodicalId":18240,"journal":{"name":"Materials Science in Semiconductor Processing","volume":"186 ","pages":"Article 109116"},"PeriodicalIF":4.2,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-15DOI: 10.1016/j.mssp.2024.109119
Dylan M. Evans, Clint D. Frye
We developed a process for the fabrication of tunable single crystal diamond micro- and nanopillars, with tip widths ranging from 40 to 460 nm, densities ranging from 0.5 to 53.5 pillars/μm2, and heights greater than 4.5 μm. A self-assembled Au nanodot ensemble etch mask was formed from an annealed Au thin film. The nanodot diameter and density can be tuned using the initial film thickness. The pillars were etched from the nanodot mask using an RIE O2 plasma, which has infinite selectivity for the diamond when applied at low RF powers (50 W). Finally, the pillars can be sharpened to ∼40 nm tip widths by annealing in air at 650 °C. These pillars can be used for applications such as field effect enhancement of diamond photocathode devices, enhancement of optical emission from N-V centers, and antireflective coatings.
{"title":"Formation of tunable diamond micro- and nanopillars for field effect enhancement applications","authors":"Dylan M. Evans, Clint D. Frye","doi":"10.1016/j.mssp.2024.109119","DOIUrl":"10.1016/j.mssp.2024.109119","url":null,"abstract":"<div><div>We developed a process for the fabrication of tunable single crystal diamond micro- and nanopillars, with tip widths ranging from 40 to 460 nm, densities ranging from 0.5 to 53.5 pillars/μm<sup>2</sup>, and heights greater than 4.5 μm. A self-assembled Au nanodot ensemble etch mask was formed from an annealed Au thin film. The nanodot diameter and density can be tuned using the initial film thickness. The pillars were etched from the nanodot mask using an RIE O<sub>2</sub> plasma, which has infinite selectivity for the diamond when applied at low RF powers (50 W). Finally, the pillars can be sharpened to ∼40 nm tip widths by annealing in air at 650 °C. These pillars can be used for applications such as field effect enhancement of diamond photocathode devices, enhancement of optical emission from N-V centers, and antireflective coatings.</div></div>","PeriodicalId":18240,"journal":{"name":"Materials Science in Semiconductor Processing","volume":"187 ","pages":"Article 109119"},"PeriodicalIF":4.2,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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