The p-type Ge doped Fe0.4Co3.6Sb12-xGex skutterudites with multi-scaled impurity dots（500 nm-2 mm） were successfully prepared by using melt-quenching（MQ） and subsequent spark plasma sintering（SPS） technique. Com...The p-type Ge doped Fe0.4Co3.6Sb12-xGex skutterudites with multi-scaled impurity dots（500 nm-2 mm） were successfully prepared by using melt-quenching（MQ） and subsequent spark plasma sintering（SPS） technique. Compared with traditional method, the new technology significantly shortened the processing time from several days to less than 24 hours. The phase of impurity dots was demonstrated to be CoSb through analysis of X-ray diffraction（XRD） and energy-dispersive spectrum（EDS）. Impurity dots were induced by Ge substitution of Sb in the non-equilibrium synthesized process. Due to the abandonment of the long reaction of annealing crystallization, a few of Ge atoms would fail to substitute Sb site of skutterudite in this non-equilibrium synthesized process, leading to that the multi-scaled impurity dots randomly distributed in the matrix of skutterudite Fe0.4Co3.6Sb12-xGex. The combination of multi-scaled impurity dots scattering long wavelength heat-carrying phonons and the point defect scattering short and middle wavelength heat-carrying phonons dramatically made the 22.2% reduction of lattice thermal conductivity. As a result, compared with unsubstituted sample of Fe0.4Co3.6Sb12, the maximum ZT value was increased by 30.5%. Thus, the two marked features of this new synthesis process, the shortened preparation time and the enhanced thermoelectric performance, would make a promising commercial application in the future.展开更多
The CuxSi（1-x） thin films have been grown by pulsed laser deposition（PLD） with in situ annealing on Si（001） and Si（111）,respectively.The transformation of phase was detected by X-ray diffraction（XRD）.The res...The CuxSi（1-x） thin films have been grown by pulsed laser deposition（PLD） with in situ annealing on Si（001） and Si（111）,respectively.The transformation of phase was detected by X-ray diffraction（XRD）.The results showed that the as-deposited films were composed of Cu on both Si（001） and Si（111）.The annealed thin films consisted of Cu ＋η ＂-Cu3Si on Si（001） while Cu ＋η＇-Cu3Si on Si（111）,respectively,at annealed temperature（Ta）= 300-600℃.With the further increasing of Ta,at Ta= 700℃,there was only one main phase,η＂-Cu3Si on Si（001） while η＇-Cu3Si on Si（111）,respectively.The annealed thin films transformed from continuous dense structure to scattered-grain morphology with increasing Ta detected by field emission scanning electron microscope（FESEM）.It was also showed that the grain size would enlarge with increasing annealing time（ta）.展开更多
Vanadium films were deposited on Si(100)substrates at room temperature by direct current(DC)magnetron sputtering.The microstructure and surface morphology were studied using scanning electron microscopy(SEM)and atomic...Vanadium films were deposited on Si(100)substrates at room temperature by direct current(DC)magnetron sputtering.The microstructure and surface morphology were studied using scanning electron microscopy(SEM)and atomic force microscope(AFM).The oxidation resistance of films in air was studied using X-ray photoelectron spectroscopy(XPS)and transmission electron microscopy(TEM).The results showed that the amorphous vanadium film with a flatter surface had higher oxidation resistance than the crystalline film when exposed to atmosphere.The rapid formation of the thin oxide layer of amorphous vanadium film could protect the film from sustained oxidation,and the relative reasons were discussed.展开更多
基金the National Natural Science Foundation of China(Nos.5137218 and 51521001)the 111 Project(B13035)+4 种基金the International Science&Technology Cooperation Program of China(2014DFA53090)the Natural Science Foundation of Hubei Province,China(2016CFA006)the Fundamental Research Funds for the Central Universities(WUT:2017II43GX,2017III032,2017-YB-004)the Science Challenge Project(No.TZ2016001)the State Key Laboratory of Advanced Technology for Materials Synthesis and Processing(WUT,No:2017-KF-5)
文摘The p-type Ge doped Fe0.4Co3.6Sb12-xGex skutterudites with multi-scaled impurity dots（500 nm-2 mm） were successfully prepared by using melt-quenching（MQ） and subsequent spark plasma sintering（SPS） technique. Compared with traditional method, the new technology significantly shortened the processing time from several days to less than 24 hours. The phase of impurity dots was demonstrated to be CoSb through analysis of X-ray diffraction（XRD） and energy-dispersive spectrum（EDS）. Impurity dots were induced by Ge substitution of Sb in the non-equilibrium synthesized process. Due to the abandonment of the long reaction of annealing crystallization, a few of Ge atoms would fail to substitute Sb site of skutterudite in this non-equilibrium synthesized process, leading to that the multi-scaled impurity dots randomly distributed in the matrix of skutterudite Fe0.4Co3.6Sb12-xGex. The combination of multi-scaled impurity dots scattering long wavelength heat-carrying phonons and the point defect scattering short and middle wavelength heat-carrying phonons dramatically made the 22.2% reduction of lattice thermal conductivity. As a result, compared with unsubstituted sample of Fe0.4Co3.6Sb12, the maximum ZT value was increased by 30.5%. Thus, the two marked features of this new synthesis process, the shortened preparation time and the enhanced thermoelectric performance, would make a promising commercial application in the future.
基金Funded by National Natural Science Foundation of China(Nos.51102101,51272196,51372188,51521001)the 111 Project(No.B13035)+2 种基金the International Science&Technology Cooperation Program of China(No.2014DFA53090)the Natural Science Foundation of Hubei Province,China(No.2014CFB870)the Fundamental Research Funds for the Central Universities,China(No.WUT:2015III023)
文摘The CuxSi（1-x） thin films have been grown by pulsed laser deposition（PLD） with in situ annealing on Si（001） and Si（111）,respectively.The transformation of phase was detected by X-ray diffraction（XRD）.The results showed that the as-deposited films were composed of Cu on both Si（001） and Si（111）.The annealed thin films consisted of Cu ＋η ＂-Cu3Si on Si（001） while Cu ＋η＇-Cu3Si on Si（111）,respectively,at annealed temperature（Ta）= 300-600℃.With the further increasing of Ta,at Ta= 700℃,there was only one main phase,η＂-Cu3Si on Si（001） while η＇-Cu3Si on Si（111）,respectively.The annealed thin films transformed from continuous dense structure to scattered-grain morphology with increasing Ta detected by field emission scanning electron microscope（FESEM）.It was also showed that the grain size would enlarge with increasing annealing time（ta）.
基金Funded by the Science Challenge Project(No.TZ2016001)the National Natural Science Foundation of China(Nos.11602251,51861145306 and 51872212)+3 种基金the 111 Project(No.B13035)Joint Fund of Ministry of Education for Pre-research of Equipment(No.6141A02022257)supported by the International Science&Technology Cooperation Program of China(Nos.2018YFE0103600,2014DFA53090)the Technological Innovation of Hubei Province,China(No.2019AAA030)。
文摘Vanadium films were deposited on Si(100)substrates at room temperature by direct current(DC)magnetron sputtering.The microstructure and surface morphology were studied using scanning electron microscopy(SEM)and atomic force microscope(AFM).The oxidation resistance of films in air was studied using X-ray photoelectron spectroscopy(XPS)and transmission electron microscopy(TEM).The results showed that the amorphous vanadium film with a flatter surface had higher oxidation resistance than the crystalline film when exposed to atmosphere.The rapid formation of the thin oxide layer of amorphous vanadium film could protect the film from sustained oxidation,and the relative reasons were discussed.
