This paper presents the design, fabrication, and preliminary experimental result of an electric field microsensor based on the structure of piezoelectric interdigitated cantilevers with staggered vertical vibration mo...This paper presents the design, fabrication, and preliminary experimental result of an electric field microsensor based on the structure of piezoelectric interdigitated cantilevers with staggered vertical vibration mode. The working principle of this electric field microsensor is demonstrated, and the induced charges and structural parameters of this microsensor are simulated by the finite element method. The electric field microsensor was fabricated by Micro-Electro Mechanical Systems(MEMS) technique. Each cantilever is a multilayer compound structure(Al/Si3N4/ Pt/PZT/Pt/ Ti/SiO 2/Si), and Piezoelectric, PieZ oelectric ceramic Transducer(PZT)(PbZ rxTi(1–x)O3) layer, prepared by sol-gel method, is used as the piezoelectric material to drive the cantilevers vibrating. This electric field microsensor was tested under the DC electric field with the field intensity from 0 to 5×104 V/m. The output voltage signal of the electric field microsensor has a good linear relationship to the intensity of applied electric field. The performance could be improved with the optimized design of structure, and reformative fabrication processes of PZT material.展开更多
Doping is critical for inducing ferroelectricity in hafnia films,yet the underlying mechanisms remain debated.Here,through first-principles studies,we elucidate the pivotal role played by the complex phase transition ...Doping is critical for inducing ferroelectricity in hafnia films,yet the underlying mechanisms remain debated.Here,through first-principles studies,we elucidate the pivotal role played by the complex phase transition mechanisms under carrier doping in understanding the origin of hafnia ferroelectricity.Specifically,electron doping orchestrates a metastable polar phase to stable antipolar phase transformation,driven by strong screening effects and weakened nonpolar covalent bonds,making n-type dopants rare.Conversely,weak screening effect and enhanced polar covalent bonding strengthen robust ferroelectricity,enabling significant ground-state phase transitions from the monoclinic to the polar orthorhombic phase and finally to the cubic phase under hole doping,a phenomenon prevalent in hafnia-based films doped with p-type dopants.Furthermore,this holeenhanced polar distortion also results in an inverse size effect in hafnia ferroelectric films,unlike perovskite ferroelectrics.Our findings offer new insights into the preparation of robust hafnia-based ferroelectric films through doping or interface engineering.展开更多
Tin sulfide (SnS) has analogous structural features to tin selenide (SnSe), but contains more abundant resources as compared with SnSe. SnS has elicited attention as a potential eco-friendly therm oelectric (TE) mater...Tin sulfide (SnS) has analogous structural features to tin selenide (SnSe), but contains more abundant resources as compared with SnSe. SnS has elicited attention as a potential eco-friendly therm oelectric (TE) material. However, the intrinsic carrier concentration of SnS is very low, thereby hindering the performance improvement of the material. This study proposes that the TE properties of polycrystalline Nadoped SnS (synthesized through an improved chemical coprecipitation) can be significantly enhanced. The maximum power factor (PF) of 362 μW m^-1K^-2 at 873 K was achieved, presenting a state-of-the-art value for the polycrystalline SnS. Considering the merits of the improved electrical properties and lower thermal conductivity of SnS, the highest ZT was up to 0.52 at 873 K even without intentional chemical doping. This study offers an effective approach for improving the PF to achieve high ZT in SnS. Hence, we expect that this new perspective can be extended to other dopants and broaden the scope of synthesis technology.展开更多
文摘This paper presents the design, fabrication, and preliminary experimental result of an electric field microsensor based on the structure of piezoelectric interdigitated cantilevers with staggered vertical vibration mode. The working principle of this electric field microsensor is demonstrated, and the induced charges and structural parameters of this microsensor are simulated by the finite element method. The electric field microsensor was fabricated by Micro-Electro Mechanical Systems(MEMS) technique. Each cantilever is a multilayer compound structure(Al/Si3N4/ Pt/PZT/Pt/ Ti/SiO 2/Si), and Piezoelectric, PieZ oelectric ceramic Transducer(PZT)(PbZ rxTi(1–x)O3) layer, prepared by sol-gel method, is used as the piezoelectric material to drive the cantilevers vibrating. This electric field microsensor was tested under the DC electric field with the field intensity from 0 to 5×104 V/m. The output voltage signal of the electric field microsensor has a good linear relationship to the intensity of applied electric field. The performance could be improved with the optimized design of structure, and reformative fabrication processes of PZT material.
基金supported by financial support from the National Natural Science Foundation of China(Grant Nos.92164108 and U23A20322,51971188,51471139)the National Key Research and Development Program of China(2023YFF0719600)+4 种基金Hunan Provincial Natural Science Foundation(Grant Nos.2023JJ50009 and 2023JJ30599)the Guangdong Provincial Key Laboratory Program from the Department of Science and Technology of Guangdong Province(2021B1212040001)the Outstanding Youth Science Foundation of Hunan Province,China(Grant No.2021JJ20041)the Key Project of Scientific Research Fund of Hunan Provincial Education Department(Grant No.23A0150)the Chongqing Municipal Education Commission Science and Technology Research Program Youth Project(KJQN202101423).
文摘Doping is critical for inducing ferroelectricity in hafnia films,yet the underlying mechanisms remain debated.Here,through first-principles studies,we elucidate the pivotal role played by the complex phase transition mechanisms under carrier doping in understanding the origin of hafnia ferroelectricity.Specifically,electron doping orchestrates a metastable polar phase to stable antipolar phase transformation,driven by strong screening effects and weakened nonpolar covalent bonds,making n-type dopants rare.Conversely,weak screening effect and enhanced polar covalent bonding strengthen robust ferroelectricity,enabling significant ground-state phase transitions from the monoclinic to the polar orthorhombic phase and finally to the cubic phase under hole doping,a phenomenon prevalent in hafnia-based films doped with p-type dopants.Furthermore,this holeenhanced polar distortion also results in an inverse size effect in hafnia ferroelectric films,unlike perovskite ferroelectrics.Our findings offer new insights into the preparation of robust hafnia-based ferroelectric films through doping or interface engineering.
基金supported by the National Key R&D Program of China (2018YFB0703603)the Basic Science Center Project of National Natural Science Foundation of China (NSFC, 51788104)the NSFC (11474176)
文摘Tin sulfide (SnS) has analogous structural features to tin selenide (SnSe), but contains more abundant resources as compared with SnSe. SnS has elicited attention as a potential eco-friendly therm oelectric (TE) material. However, the intrinsic carrier concentration of SnS is very low, thereby hindering the performance improvement of the material. This study proposes that the TE properties of polycrystalline Nadoped SnS (synthesized through an improved chemical coprecipitation) can be significantly enhanced. The maximum power factor (PF) of 362 μW m^-1K^-2 at 873 K was achieved, presenting a state-of-the-art value for the polycrystalline SnS. Considering the merits of the improved electrical properties and lower thermal conductivity of SnS, the highest ZT was up to 0.52 at 873 K even without intentional chemical doping. This study offers an effective approach for improving the PF to achieve high ZT in SnS. Hence, we expect that this new perspective can be extended to other dopants and broaden the scope of synthesis technology.
