Pub Date : 2025-12-24DOI: 10.1016/j.vacuum.2025.115046
Guanjun Chen , Dong Yang , Jin Zhang , Qinchuan Zhu , Guoyu Ren , Hao Tian , Ji Lei , Xianzhu Zhuang , Jianfeng Huang , Lixiong Yin , Xingang Kong
In this study, we developed a urea-thermal synthesis method featuring simple operation, and successfully prepared pure-phase ZnIn2S4 materials by regulating different holding durations. The experimental results showed that at a reaction temperature of 180 °C, only 2 h of heat preservation is required to obtain ZnIn2S4 particles that completely match the standard card. All samples prepared with different reaction durations exhibited excellent photocatalytic activity. Beyond developing a simplified synthetic route for ZnIn2S4 photocatalysts, this work offers new research approach to the synthesis and application of photocatalytic materials.
{"title":"ZnIn2S4 was prepared by urea-thermal synthesis method for photocatalytic hydrogen evolution","authors":"Guanjun Chen , Dong Yang , Jin Zhang , Qinchuan Zhu , Guoyu Ren , Hao Tian , Ji Lei , Xianzhu Zhuang , Jianfeng Huang , Lixiong Yin , Xingang Kong","doi":"10.1016/j.vacuum.2025.115046","DOIUrl":"10.1016/j.vacuum.2025.115046","url":null,"abstract":"<div><div>In this study, we developed a urea-thermal synthesis method featuring simple operation, and successfully prepared pure-phase ZnIn<sub>2</sub>S<sub>4</sub> materials by regulating different holding durations. The experimental results showed that at a reaction temperature of 180 °C, only 2 h of heat preservation is required to obtain ZnIn<sub>2</sub>S<sub>4</sub> particles that completely match the standard card. All samples prepared with different reaction durations exhibited excellent photocatalytic activity. Beyond developing a simplified synthetic route for ZnIn<sub>2</sub>S<sub>4</sub> photocatalysts, this work offers new research approach to the synthesis and application of photocatalytic materials.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"246 ","pages":"Article 115046"},"PeriodicalIF":3.9,"publicationDate":"2025-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-12-24DOI: 10.1016/j.vacuum.2025.115050
Dengwen Yuan , Yu Zhong , Chuibang Jia , Zedong Liu , Yaxin Li , Jingjing Cai , Rui Zhang , Mingsheng Xu , Xiangang Xu , Jisheng Han
Small-angle etching of SiC is widely applied in the fabrication of advanced power and optoelectronic devices. Therefore, this paper presents a method for forming small-angle trenches with high surface quality on 4H-SiC by inductively coupled plasma (ICP) etching. By combining optical emission spectroscopy (OES) technique, the effects of ICP power, RF power and the O2 ratio in the SF6/O2 gas mixture on the SiC etch angle and surface roughness were investigated. Our results suggest that the O2 ratio plays the dominant role among the three factors. Based on the analysis of characteristic peaks in OES, a model parameter K was established for the first time which exhibits a strong nonlinear exponential correlation with the SiC etch angle. This enables in-situ estimation of the etch angle without requiring additional complex measurements. Finally, the SiC avalanche photodiode (APD) was fabricated under the optimal etching condition. The device achieves a dark current on the order of pA and a maximum gain exceeding 106. This study provides key insights for the development and fabrication of small-angle beveled SiC devices with simplified processes.
{"title":"Investigation of small-angle SiC ICP etching assisted by optical emission spectroscopy diagnostics","authors":"Dengwen Yuan , Yu Zhong , Chuibang Jia , Zedong Liu , Yaxin Li , Jingjing Cai , Rui Zhang , Mingsheng Xu , Xiangang Xu , Jisheng Han","doi":"10.1016/j.vacuum.2025.115050","DOIUrl":"10.1016/j.vacuum.2025.115050","url":null,"abstract":"<div><div>Small-angle etching of SiC is widely applied in the fabrication of advanced power and optoelectronic devices. Therefore, this paper presents a method for forming small-angle trenches with high surface quality on 4H-SiC by inductively coupled plasma (ICP) etching. By combining optical emission spectroscopy (OES) technique, the effects of ICP power, RF power and the O<sub>2</sub> ratio in the SF<sub>6</sub>/O<sub>2</sub> gas mixture on the SiC etch angle and surface roughness were investigated. Our results suggest that the O<sub>2</sub> ratio plays the dominant role among the three factors. Based on the analysis of characteristic peaks in OES, a model parameter K was established for the first time which exhibits a strong nonlinear exponential correlation with the SiC etch angle. This enables in-situ estimation of the etch angle without requiring additional complex measurements. Finally, the SiC avalanche photodiode (APD) was fabricated under the optimal etching condition. The device achieves a dark current on the order of pA and a maximum gain exceeding 10<sup>6</sup>. This study provides key insights for the development and fabrication of small-angle beveled SiC devices with simplified processes.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"246 ","pages":"Article 115050"},"PeriodicalIF":3.9,"publicationDate":"2025-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-12-23DOI: 10.1016/j.vacuum.2025.115048
Jing Yan , Yun Geng , Hannan Shan , Yiwen Chen , Yingsan Geng , Zhiyuan Liu
This paper presents a systematic experimental investigation into the prestrike phenomena and underlying mechanisms in double-break vacuum circuit breakers during capacitive switching operations. The study focuses on the prestrike characteristics under high-frequency inrush currents of 5 kA and 20 kA. It innovatively elucidates the influence of inrush current amplitude on key parameters, including the prestrike gap length, electric field strength, inrush current chopping behavior, arcing time, and field emission properties of the contacts. Experimental results demonstrate that a high-amplitude inrush current (20 kA) significantly increases the prestrike gap length (with the d90 value increasing by approximately 2 mm) and reduces its dispersion (by up to 40 %) compared to the 5 kA condition. Furthermore, this condition reduces the frequency of inrush current chopping but prolongs the arcing time. Additionally, the high-energy inrush current leads to a notable increase in the field enhancement factor of the contact surfaces, indicating more severe surface degradation. This research provides crucial experimental evidence and theoretical support for the optimized design and engineering application of double-break vacuum circuit breakers in phase-controlled switching.
{"title":"Prestrike characteristics and mechanism of double-break vacuum circuit breakers under high-frequency capacitive inrush current","authors":"Jing Yan , Yun Geng , Hannan Shan , Yiwen Chen , Yingsan Geng , Zhiyuan Liu","doi":"10.1016/j.vacuum.2025.115048","DOIUrl":"10.1016/j.vacuum.2025.115048","url":null,"abstract":"<div><div>This paper presents a systematic experimental investigation into the prestrike phenomena and underlying mechanisms in double-break vacuum circuit breakers during capacitive switching operations. The study focuses on the prestrike characteristics under high-frequency inrush currents of 5 kA and 20 kA. It innovatively elucidates the influence of inrush current amplitude on key parameters, including the prestrike gap length, electric field strength, inrush current chopping behavior, arcing time, and field emission properties of the contacts. Experimental results demonstrate that a high-amplitude inrush current (20 kA) significantly increases the prestrike gap length (with the <em>d</em><sub><em>90</em></sub> value increasing by approximately 2 mm) and reduces its dispersion (by up to 40 %) compared to the 5 kA condition. Furthermore, this condition reduces the frequency of inrush current chopping but prolongs the arcing time. Additionally, the high-energy inrush current leads to a notable increase in the field enhancement factor of the contact surfaces, indicating more severe surface degradation. This research provides crucial experimental evidence and theoretical support for the optimized design and engineering application of double-break vacuum circuit breakers in phase-controlled switching.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"246 ","pages":"Article 115048"},"PeriodicalIF":3.9,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Development of highly efficient transparent oxide thermoelectric thin films is key to next-generation eco-friendly, portable, and sustainable electronic devices. In this work, we report enhanced electrical transport and thermoelectric performance in ZnO and Al-doped ZnO thin films grown by pulsed laser deposition (PLD). Al doping resulted a 3-fold enhancement in electrical conductivity from 397 S cm−1 (undoped ZnO) to 1250 S cm−1 (Zn0.97Al0.03O). A maximum thermoelectric power factor of ∼1.2 mW m−1 K−2 for undoped ZnO and ∼0.77 mW m−1 K−2 for Zn0.97Al0.03O thin films was achieved at 750 K. The large power factor is attributed to a synergistic effect of improved electrical conductivity, arising from native oxygen vacancy defects and substitutional Al3+ donors, together with higher Seebeck coefficients associated with dominant acoustic phonon scattering. These findings demonstrate the potential of Al-doped ZnO thin films as promising candidates for high-performance, transparent solid-state thermoelectric devices.
高效透明氧化物热电薄膜的开发是下一代环保、便携和可持续电子设备的关键。在这项工作中，我们报道了通过脉冲激光沉积（PLD）生长的ZnO和al掺杂ZnO薄膜的电输运和热电性能的增强。Al掺杂导致导电率从397 S cm−1（未掺杂ZnO）提高到1250 S cm−1 (zn0.97 al0.030)，提高了3倍。在750 K时，未掺杂ZnO薄膜的最大热电功率因子为~ 1.2 mW m−1 K−2,zn0.97 al0.030薄膜的最大热电功率因子为~ 0.77 mW m−1 K−2。较大的功率因数归因于由天然氧空位缺陷和取代的Al3+供体引起的电导率改善的协同效应，以及与主要声子散射相关的较高塞贝克系数。这些发现证明了al掺杂ZnO薄膜作为高性能，透明固态热电器件的有希望的候选者的潜力。
{"title":"Enhanced electrical transport and thermoelectric performance of nanostructured Al-doped ZnO thin films grown by pulsed laser deposition","authors":"Vasudevan Jayaseelan , Navaneethan Mani , Senthil Kumar Eswaran","doi":"10.1016/j.vacuum.2025.115033","DOIUrl":"10.1016/j.vacuum.2025.115033","url":null,"abstract":"<div><div>Development of highly efficient transparent oxide thermoelectric thin films is key to next-generation eco-friendly, portable, and sustainable electronic devices. In this work, we report enhanced electrical transport and thermoelectric performance in ZnO and Al-doped ZnO thin films grown by pulsed laser deposition (PLD). Al doping resulted a 3-fold enhancement in electrical conductivity from 397 S cm<sup>−1</sup> (undoped ZnO) to 1250 S cm<sup>−1</sup> (Zn<sub>0</sub>.<sub>97</sub>Al<sub>0</sub>.<sub>03</sub>O). A maximum thermoelectric power factor of ∼1.2 mW m<sup>−1</sup> K<sup>−2</sup> for undoped ZnO and ∼0.77 mW m<sup>−1</sup> K<sup>−2</sup> for Zn<sub>0</sub>.<sub>97</sub>Al<sub>0</sub>.<sub>03</sub>O thin films was achieved at 750 K. The large power factor is attributed to a synergistic effect of improved electrical conductivity, arising from native oxygen vacancy defects and substitutional Al<sup>3+</sup> donors, together with higher Seebeck coefficients associated with dominant acoustic phonon scattering. These findings demonstrate the potential of Al-doped ZnO thin films as promising candidates for high-performance, transparent solid-state thermoelectric devices.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"246 ","pages":"Article 115033"},"PeriodicalIF":3.9,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-12-23DOI: 10.1016/j.vacuum.2025.115047
Xin Li , Wenqiang Li , Yinhui Kan , Lingfei Xiao , Zhifeng Ye
Liquid ring vacuum pumps show potential for aircraft fuel systems to enhance the self-priming capability of main impeller pumps but research on characteristics of double-acting liquid ring vacuum pumps and their aviation applications remain extremely limited. To investigate the internal flow field and external characteristics of an aviation double-acting high-speed fuel liquid ring vacuum pump at different flight altitudes, a combined approach of experiment and multiphase flow simulation was adopted. Results indicate that numerical simulations of flow rate and power consumption under various operating conditions generally align with experimental trends. Hydraulic losses arising from complex unsteady gas-liquid two-phase flow are identified as a significant factor affecting its energy consumption and efficiency. The gas-liquid two-phase flow field within the double-acting liquid ring vacuum pump exhibits central symmetry with the vorticity intensity of gas phase exceeding that of liquid phase. Pressure within the pump fluctuates periodically, revealing strong rotor-stator interaction effects and frequency domain characteristics of pressure pulsations vary significantly across different sections. Flow field feature and performance metrics are closely linked and the hydraulic efficiency is related to compression work state and energy dissipation. As altitude increases, the outlet initial region state gradually transitions from over-compression to under-compression with additional efficiency losses caused by over-compression, outlet backflow, and clearance leakage. Total entropy generation exhibits a continuous increase, while both flow rate and efficiency demonstrate a trend of initially rising slowly followed by a rapid decline, with the peak efficiency from both experiment and simulation occurs at the 5 km altitude condition.
{"title":"Flow field dynamics and efficiency-energy response of aviation double-acting liquid ring vacuum pump under variable altitude conditions","authors":"Xin Li , Wenqiang Li , Yinhui Kan , Lingfei Xiao , Zhifeng Ye","doi":"10.1016/j.vacuum.2025.115047","DOIUrl":"10.1016/j.vacuum.2025.115047","url":null,"abstract":"<div><div>Liquid ring vacuum pumps show potential for aircraft fuel systems to enhance the self-priming capability of main impeller pumps but research on characteristics of double-acting liquid ring vacuum pumps and their aviation applications remain extremely limited. To investigate the internal flow field and external characteristics of an aviation double-acting high-speed fuel liquid ring vacuum pump at different flight altitudes, a combined approach of experiment and multiphase flow simulation was adopted. Results indicate that numerical simulations of flow rate and power consumption under various operating conditions generally align with experimental trends. Hydraulic losses arising from complex unsteady gas-liquid two-phase flow are identified as a significant factor affecting its energy consumption and efficiency. The gas-liquid two-phase flow field within the double-acting liquid ring vacuum pump exhibits central symmetry with the vorticity intensity of gas phase exceeding that of liquid phase. Pressure within the pump fluctuates periodically, revealing strong rotor-stator interaction effects and frequency domain characteristics of pressure pulsations vary significantly across different sections. Flow field feature and performance metrics are closely linked and the hydraulic efficiency is related to compression work state and energy dissipation. As altitude increases, the outlet initial region state gradually transitions from over-compression to under-compression with additional efficiency losses caused by over-compression, outlet backflow, and clearance leakage. Total entropy generation exhibits a continuous increase, while both flow rate and efficiency demonstrate a trend of initially rising slowly followed by a rapid decline, with the peak efficiency from both experiment and simulation occurs at the 5 km altitude condition.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"246 ","pages":"Article 115047"},"PeriodicalIF":3.9,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145885210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-12-23DOI: 10.1016/j.vacuum.2025.115043
Rui Wu , Lingjia Meng , Jinxiang Deng , Yiming Shi , Xue Meng , Jiawei Xu , Weiman Liu , Weijian Zhai , Junhua Meng , Le Kong , Xiaolei Yang
Nb and H co-doped Ga2O3 thin films were deposited on silicon (Si) and quartz substrates by RF magnetron sputtering, followed by a post-deposition annealing process. The study elucidated the synergistic effects of Nb and H doping on β-Ga2O3 formation. Nb doping promoted nucleation and growth, reduced grain boundary defects, suppressed non-radiative recombination, stabilized Ga3+, and inhibited oxygen vacancy (OV) formation. Concurrently, H passivated intrinsic OV by forming neutral complexes, thereby lowering active OV concentration. This dual doping strategy significantly enhanced electrical properties: carrier mobility increased from 1.6 to 18.9 cm2 V−1 s−1. Consequently, the Si/Nb-H-Ga2O3/Au MSM photodetector exhibited dramatically improved performance, with a photo-to-dark current ratio of 18.85 and a responsivity of 0.812 A/W at 20 V-representing 54-fold and 10-fold enhancements over the pristine Ga2O3 device, respectively. This work demonstrates the potential of Ga2O3 for developing high-power and high-efficiency electronic devices.
{"title":"Effects of Nb and Nb-H Co-doping on the Electrical Properties of β-Ga2O3","authors":"Rui Wu , Lingjia Meng , Jinxiang Deng , Yiming Shi , Xue Meng , Jiawei Xu , Weiman Liu , Weijian Zhai , Junhua Meng , Le Kong , Xiaolei Yang","doi":"10.1016/j.vacuum.2025.115043","DOIUrl":"10.1016/j.vacuum.2025.115043","url":null,"abstract":"<div><div>Nb and H co-doped Ga<sub>2</sub>O<sub>3</sub> thin films were deposited on silicon (Si) and quartz substrates by RF magnetron sputtering, followed by a post-deposition annealing process. The study elucidated the synergistic effects of Nb and H doping on β-Ga<sub>2</sub>O<sub>3</sub> formation. Nb doping promoted nucleation and growth, reduced grain boundary defects, suppressed non-radiative recombination, stabilized Ga<sup>3+</sup>, and inhibited oxygen vacancy (O<sub>V</sub>) formation. Concurrently, H passivated intrinsic O<sub>V</sub> by forming neutral complexes, thereby lowering active O<sub>V</sub> concentration. This dual doping strategy significantly enhanced electrical properties: carrier mobility increased from 1.6 to 18.9 cm<sup>2</sup> V<sup>−1</sup> s<sup>−1</sup>. Consequently, the Si/Nb-H-Ga<sub>2</sub>O<sub>3</sub>/Au MSM photodetector exhibited dramatically improved performance, with a photo-to-dark current ratio of 18.85 and a responsivity of 0.812 A/W at 20 V-representing 54-fold and 10-fold enhancements over the pristine Ga<sub>2</sub>O<sub>3</sub> device, respectively. This work demonstrates the potential of Ga<sub>2</sub>O<sub>3</sub> for developing high-power and high-efficiency electronic devices.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"246 ","pages":"Article 115043"},"PeriodicalIF":3.9,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-12-23DOI: 10.1016/j.vacuum.2025.115041
Dun-Bao Ruan , Kuei-Shu Chang-Liao , Hsin-I Yeh , Bo-Syun Syu , Chia-Chien Liu , Guan-Ting Liu , Chih-Wei Liu , Jia-Long Xiang , Ze-Fu Zhao , Kai-Jhih Gan
In order to suppress the interface and border trap generation, an in-situ low-temperature hydrogen (H2) pre-trimming treatment was applied on the germanium (Ge) substrate before an alloy-like hafnium nitride interfacial layer formation during the Ge MOS device fabrication. By systematically modulating H2 cycles, the influence of hydrogenation on surface roughness, oxygen vacancy, interface and border trap were investigated in details. Besides, the internal reaction mechanism and physical model were well studied by material analysis and electrical characterization. As a result, the Ge MOS device after 5 cycle H2 treatment exhibits the lowest surface roughness, oxygen vacancy, equivalent oxide thickness, interface trap density, border trap numbers, and best reliability characteristics. This work could provide a promising pathway for interface engineering in Ge MOS devices.
{"title":"Surface engineering on P-substrate Ge MOS device with in-situ low temperature H2 pre-trimming treatment","authors":"Dun-Bao Ruan , Kuei-Shu Chang-Liao , Hsin-I Yeh , Bo-Syun Syu , Chia-Chien Liu , Guan-Ting Liu , Chih-Wei Liu , Jia-Long Xiang , Ze-Fu Zhao , Kai-Jhih Gan","doi":"10.1016/j.vacuum.2025.115041","DOIUrl":"10.1016/j.vacuum.2025.115041","url":null,"abstract":"<div><div>In order to suppress the interface and border trap generation, an in-situ low-temperature hydrogen (H<sub>2</sub>) pre-trimming treatment was applied on the germanium (Ge) substrate before an alloy-like hafnium nitride interfacial layer formation during the Ge MOS device fabrication. By systematically modulating H<sub>2</sub> cycles, the influence of hydrogenation on surface roughness, oxygen vacancy, interface and border trap were investigated in details. Besides, the internal reaction mechanism and physical model were well studied by material analysis and electrical characterization. As a result, the Ge MOS device after 5 cycle H<sub>2</sub> treatment exhibits the lowest surface roughness, oxygen vacancy, equivalent oxide thickness, interface trap density, border trap numbers, and best reliability characteristics. This work could provide a promising pathway for interface engineering in Ge MOS devices.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"246 ","pages":"Article 115041"},"PeriodicalIF":3.9,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-12-23DOI: 10.1016/j.vacuum.2025.115042
Qingshan Zhou, Deli Kong, Xiaojing Xu, Siyuan Yin
Rare earth multi-element microalloying is a crucial technique for enhancing the overall performance of Al-Zn-Mg-Cu-Zr-Ti alloys. This study proposes a technical approach involving the composite addition of low diffusion rate rare earth elements La and Er. This method has successfully reduced the size of nanograins and lattice mismatch, thereby significantly improving the comprehensive performance of the alloy. The results reveal that the combined addition of La and Er can induce the formation of Al3(Zr,Er,La) nanoparticles, whose average size and lattice misfit degree are significantly lower than those of Al3Zr nanoparticles in the base alloy. These Al3(Zr,Er,La) nanoparticles can effectively inhibit the recrystallization behavior during heat treatments, reducing the alloy's recrystallization fraction from 53.5 % to 42.8 % and refining the average grain size from 4.67 μm to 3.62 μm. Meanwhile, the Al3(Zr,Er,La) nanoparticles impede dislocation motion and increase the alloy's dislocation density; additionally, they enhance the nucleation rate of aging precipitates through the lattice misfit effect with the aluminum matrix, achieving the refinement and volume fraction increase of aging precipitates. Thus, the yield strength of the alloy has enhanced. Furthermore, the combined addition reduces the continuity of grain boundary precipitates (GBPs), enhancing the alloy's intergranular corrosion (IGC) resistance.
{"title":"Effect of rare-earth (Er-La) composite addition on the microstructure and properties of a highly alloyed Al-Zn-Mg-Cu-Zr-Ti aluminum alloy","authors":"Qingshan Zhou, Deli Kong, Xiaojing Xu, Siyuan Yin","doi":"10.1016/j.vacuum.2025.115042","DOIUrl":"10.1016/j.vacuum.2025.115042","url":null,"abstract":"<div><div>Rare earth multi-element microalloying is a crucial technique for enhancing the overall performance of Al-Zn-Mg-Cu-Zr-Ti alloys. This study proposes a technical approach involving the composite addition of low diffusion rate rare earth elements La and Er. This method has successfully reduced the size of nanograins and lattice mismatch, thereby significantly improving the comprehensive performance of the alloy. The results reveal that the combined addition of La and Er can induce the formation of Al<sub>3</sub>(Zr,Er,La) nanoparticles, whose average size and lattice misfit degree are significantly lower than those of Al<sub>3</sub>Zr nanoparticles in the base alloy. These Al<sub>3</sub>(Zr,Er,La) nanoparticles can effectively inhibit the recrystallization behavior during heat treatments, reducing the alloy's recrystallization fraction from 53.5 % to 42.8 % and refining the average grain size from 4.67 μm to 3.62 μm. Meanwhile, the Al<sub>3</sub>(Zr,Er,La) nanoparticles impede dislocation motion and increase the alloy's dislocation density; additionally, they enhance the nucleation rate of aging precipitates through the lattice misfit effect with the aluminum matrix, achieving the refinement and volume fraction increase of aging precipitates. Thus, the yield strength of the alloy has enhanced. Furthermore, the combined addition reduces the continuity of grain boundary precipitates (GBPs), enhancing the alloy's intergranular corrosion (IGC) resistance.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"246 ","pages":"Article 115042"},"PeriodicalIF":3.9,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-12-22DOI: 10.1016/j.vacuum.2025.115044
Junfeng Li, Bing Zhou, Jie Gao, Ang Li, Shengwang Yu
This study investigates the synergistic effects of electric fields, plasma dynamics, and interfacial processes in the hetero-nucleation of diamond through a specially designed DC pulsed forward bias-enhanced nucleation (DCP-BEN) approach. The nucleation process was monitored in real time using in-situ optical emission spectroscopy (OES), complemented by multi-scale ex-situ characterization to elucidate the underlying mechanisms. Through systematic modulation of the nucleation time, this work establishes its significant influence on both the plasma chemical environment and the morphological development of the Ir-diamond interface. An optimal nucleation window at 45 min was identified, facilitating the formation of self-organized nanogrooves (2–7 nm) and a low-mismatch Ir-diamond interface with an experimentally measured mismatch of approximately 4.7 %. This engineered interface exhibits a substantially reduced mismatch compared to the theoretical prediction (∼7.8 %) based on bulk lattice parameters, effectively suppressing interfacial dislocations and twin boundaries during subsequent epitaxy, and yielding a high diamond nucleus density of 109∼1010 cm−2. The ideal bias conditions were determined to be a field strength of ∼1.5 × 105 V/m and a plasma sheath thickness of ∼4 mm. A nucleation mechanism involving carbon enrichment, ion bombardment, and surface reconstruction is proposed, based on the synergistic interplay among the electric field, plasma, and interface. These findings provide crucial insights into the controlled synthesis of high-density diamond films on Ir substrates.
{"title":"Unraveling the role of DC pulsed bias in diamond nucleation on iridium: A coupled study of plasma diagnostics and interface engineering","authors":"Junfeng Li, Bing Zhou, Jie Gao, Ang Li, Shengwang Yu","doi":"10.1016/j.vacuum.2025.115044","DOIUrl":"10.1016/j.vacuum.2025.115044","url":null,"abstract":"<div><div>This study investigates the synergistic effects of electric fields, plasma dynamics, and interfacial processes in the hetero-nucleation of diamond through a specially designed DC pulsed forward bias-enhanced nucleation (DCP-BEN) approach. The nucleation process was monitored in real time using in-situ optical emission spectroscopy (OES), complemented by multi-scale ex-situ characterization to elucidate the underlying mechanisms. Through systematic modulation of the nucleation time, this work establishes its significant influence on both the plasma chemical environment and the morphological development of the Ir-diamond interface. An optimal nucleation window at 45 min was identified, facilitating the formation of self-organized nanogrooves (2–7 nm) and a low-mismatch Ir-diamond interface with an experimentally measured mismatch of approximately 4.7 %. This engineered interface exhibits a substantially reduced mismatch compared to the theoretical prediction (∼7.8 %) based on bulk lattice parameters, effectively suppressing interfacial dislocations and twin boundaries during subsequent epitaxy, and yielding a high diamond nucleus density of 10<sup>9</sup>∼10<sup>10</sup> cm<sup>−2</sup>. The ideal bias conditions were determined to be a field strength of ∼1.5 × 10<sup>5</sup> V/m and a plasma sheath thickness of ∼4 mm. A nucleation mechanism involving carbon enrichment, ion bombardment, and surface reconstruction is proposed, based on the synergistic interplay among the electric field, plasma, and interface. These findings provide crucial insights into the controlled synthesis of high-density diamond films on Ir substrates.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"246 ","pages":"Article 115044"},"PeriodicalIF":3.9,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-12-22DOI: 10.1016/j.vacuum.2025.115039
Chandra Kumar , Monika Shrivastav , Jiten Yadav , Vikas Kashyap , Amit Kumar Gangawar , Arjun Kumawat , Harpreet Kaur , Kamlesh Yadav , Juan Luis Palma , Ram Pratap Yadav , Fernando Guzman , Kapil Saxena
Nickel oxide (NiO) thin films have emerged as pivotal materials for next-generation optoelectronic applications. In this work, we present a comprehensive investigation of the correlation between surface fractality, optical, electrical properties in NiO thin films, deposited by the magnetron sputtering at varying deposition times (50, 70, and 90 min). The evolution of surface morphology, quantified through power spectral density (PSD) based fractal analysis, revealed a progressive enhancement in surface complexity with deposition time, characterized by the fractal dimension (Df), ranges from 2.06 ± 0.02 to 2.24 ± 0.03. This trend reflects a transition from a kinetically limited to a diffusion-dominated growth regime. Concurrently, the roughness exponent (α) decreased from 0.94 to 0.76, whereas the growth exponent (β ≈ 0.27) remained nearly invariant, suggesting a self-affine surface evolution governed by competitive aggregation and relaxation mechanisms. Optical spectroscopy confirmed a strong interplay between the fractal scaling parameters and the optical properties. The optical band gap (Eg) exhibited a systematic redshift from 3.79 eV to 3.68 eV as Df increased, indicating that enhanced surface irregularity and nanoscale disorder facilitate localized states within the band structure. Electrical measurements further revealed a monotonic reduction in conductivity from 9 × 10−4 S cm−1 to 4 × 10−4 S cm−1 with increasing deposition time, consistent with charge carrier scattering induced by increased morphological irregularities. The relationship between fractal scaling parameters and electrical conductivity was validated using the Fal'ko–Efetov relation. The integrated structural, optical, and electrical analysis provides a mechanistic understanding of how fractal morphology governs the functional performance of NiO films. These findings highlight that controlled fractal growth in sputtered NiO enables the rational tuning of band gap and conductivity, offering a robust pathway to optimize p-type transparent electrodes and hole transport layers for high-performance optoelectronic, photovoltaic, and photoelectrochemical applications.
氧化镍（NiO）薄膜已成为下一代光电应用的关键材料。在这项工作中，我们全面研究了在不同沉积时间（50,70和90min）下磁控溅射沉积的NiO薄膜的表面分形，光学，电学性质之间的关系。基于功率谱密度（PSD）的分形分析表明，随着沉积时间的延长，表面复杂性逐渐增强，其分形维数（Df）范围为2.06±0.02 ~ 2.24±0.03。这一趋势反映了从动力限制型向扩散主导型增长体制的转变。同时，粗糙度指数（α）从0.94下降到0.76，而生长指数（β≈0.27）几乎保持不变，表明表面的自仿射演化受竞争聚集和弛豫机制的支配。光谱学证实了分形标度参数与光学性质之间有很强的相互作用。随着Df的增加，光学带隙（Eg）呈现出从3.79 eV到3.68 eV的系统红移，表明表面不规则性和纳米级无序性的增强促进了带结构内的局域化状态。电学测量进一步显示，随着沉积时间的增加，电导率从9 × 10−4 S cm−1单调降低到4 × 10−4 S cm−1，这与形貌不规则性增加引起的载流子散射一致。利用Fal 'ko-Efetov关系验证了分形标度参数与电导率之间的关系。综合结构，光学和电学分析提供了分形形态如何控制NiO薄膜功能性能的机制理解。这些发现强调了溅射NiO中可控的分形生长可以合理调节带隙和电导率，为优化高性能光电、光伏和光电化学应用的p型透明电极和空穴传输层提供了坚实的途径。
{"title":"Growth dynamics and surface scaling of air-oxidized NiO thin films from sputtered Ni","authors":"Chandra Kumar , Monika Shrivastav , Jiten Yadav , Vikas Kashyap , Amit Kumar Gangawar , Arjun Kumawat , Harpreet Kaur , Kamlesh Yadav , Juan Luis Palma , Ram Pratap Yadav , Fernando Guzman , Kapil Saxena","doi":"10.1016/j.vacuum.2025.115039","DOIUrl":"10.1016/j.vacuum.2025.115039","url":null,"abstract":"<div><div>Nickel oxide (NiO) thin films have emerged as pivotal materials for next-generation optoelectronic applications. In this work, we present a comprehensive investigation of the correlation between surface fractality, optical, electrical properties in NiO thin films, deposited by the magnetron sputtering at varying deposition times (50, 70, and 90 min). The evolution of surface morphology, quantified through power spectral density (PSD) based fractal analysis, revealed a progressive enhancement in surface complexity with deposition time, characterized by the fractal dimension (D<sub>f</sub>), ranges from 2.06 ± 0.02 to 2.24 ± 0.03. This trend reflects a transition from a kinetically limited to a diffusion-dominated growth regime. Concurrently, the roughness exponent (α) decreased from 0.94 to 0.76, whereas the growth exponent (β ≈ 0.27) remained nearly invariant, suggesting a self-affine surface evolution governed by competitive aggregation and relaxation mechanisms. Optical spectroscopy confirmed a strong interplay between the fractal scaling parameters and the optical properties. The optical band gap (E<sub>g</sub>) exhibited a systematic redshift from 3.79 eV to 3.68 eV as D<sub>f</sub> increased, indicating that enhanced surface irregularity and nanoscale disorder facilitate localized states within the band structure. Electrical measurements further revealed a monotonic reduction in conductivity from 9 × 10<sup>−4</sup> S cm<sup>−1</sup> to 4 × 10<sup>−4</sup> S cm<sup>−1</sup> with increasing deposition time, consistent with charge carrier scattering induced by increased morphological irregularities. The relationship between fractal scaling parameters and electrical conductivity was validated using the Fal'ko–Efetov relation. The integrated structural, optical, and electrical analysis provides a mechanistic understanding of how fractal morphology governs the functional performance of NiO films. These findings highlight that controlled fractal growth in sputtered NiO enables the rational tuning of band gap and conductivity, offering a robust pathway to optimize p-type transparent electrodes and hole transport layers for high-performance optoelectronic, photovoltaic, and photoelectrochemical applications.</div></div>","PeriodicalId":23559,"journal":{"name":"Vacuum","volume":"246 ","pages":"Article 115039"},"PeriodicalIF":3.9,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145885211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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