Silicon carbide(SiC)is a IV-IV compound semiconductor material with a wide band gap.Semiconductor electronic devices and circuits made from SiC are presently developed for high-temperature,high-power,and high-radiatio...Silicon carbide(SiC)is a IV-IV compound semiconductor material with a wide band gap.Semiconductor electronic devices and circuits made from SiC are presently developed for high-temperature,high-power,and high-radiation conditions,in which conventional semiconductors cannot be adequately performed.In this paper,SiH4 and C2H2 were used to synthesize SiC nano-whiskers.Metal Ni was the catalyst.SiC nanowhiskers were grown by vapor-liquid-solid mechanism.The effects of the H2 flow rate,growth temperature,catalyst thickness and growth pressure to grow SiC nano-whiskers were studied.3C-SiC thin film and nano-tips can be synthesized by controlling the growth conditions.展开更多
Te ion migration during electrochemical process is a fundamental scientifc issue for phase transition behavior and of technical importance for various functional devices,where cations or anions are active under electr...Te ion migration during electrochemical process is a fundamental scientifc issue for phase transition behavior and of technical importance for various functional devices,where cations or anions are active under electrical bias.Usually only one type of functional ion,O^(2-)or Li^(+),is activated due to their diferent migration energy barriers,cooperated by the valence change of other immobile ions in the host lattice matrix,e.g.,Co^(2+)/Co^(3+)and Mn^(3+)/Mn4+redox couples,owing to the charge neutralization.Here we select spinel Li4Ti5O12 as anode and construct an all-solid-state battery under a transmission electron microscope;a synergistic transportation of O^(2-)and Li^(+)driven by an electrical bias was directly observed at the atomic scale.A small amount of oxygen anions was extracted frstly as a result of its lowest vacancy formation energy under 2.2 V,leading to the vertical displacement of oxygen.Up to 2.7 V,an ordered phase with both Li-and O-defciency formed.Te Li^(+)and O^(2-)ions are simultaneously extracted out from the[LiO_(4)]tetrahedra due to the electroneutrality principle.Te migration paths of O and Li have been proposed and verifed by frst-principles calculations.Tese results reveal a brand new synergistic ion migration manner and may provide up-to-date insights on the transportation process of lithium ion conductors.展开更多
文摘Silicon carbide(SiC)is a IV-IV compound semiconductor material with a wide band gap.Semiconductor electronic devices and circuits made from SiC are presently developed for high-temperature,high-power,and high-radiation conditions,in which conventional semiconductors cannot be adequately performed.In this paper,SiH4 and C2H2 were used to synthesize SiC nano-whiskers.Metal Ni was the catalyst.SiC nanowhiskers were grown by vapor-liquid-solid mechanism.The effects of the H2 flow rate,growth temperature,catalyst thickness and growth pressure to grow SiC nano-whiskers were studied.3C-SiC thin film and nano-tips can be synthesized by controlling the growth conditions.
基金This work was supported by National Program on Key Basic Research Project(2014CB921002,2015CB921700)The Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB07030200)National Natural Science Foundation of China(51522212,51421002,51332001,and 11704019).
文摘Te ion migration during electrochemical process is a fundamental scientifc issue for phase transition behavior and of technical importance for various functional devices,where cations or anions are active under electrical bias.Usually only one type of functional ion,O^(2-)or Li^(+),is activated due to their diferent migration energy barriers,cooperated by the valence change of other immobile ions in the host lattice matrix,e.g.,Co^(2+)/Co^(3+)and Mn^(3+)/Mn4+redox couples,owing to the charge neutralization.Here we select spinel Li4Ti5O12 as anode and construct an all-solid-state battery under a transmission electron microscope;a synergistic transportation of O^(2-)and Li^(+)driven by an electrical bias was directly observed at the atomic scale.A small amount of oxygen anions was extracted frstly as a result of its lowest vacancy formation energy under 2.2 V,leading to the vertical displacement of oxygen.Up to 2.7 V,an ordered phase with both Li-and O-defciency formed.Te Li^(+)and O^(2-)ions are simultaneously extracted out from the[LiO_(4)]tetrahedra due to the electroneutrality principle.Te migration paths of O and Li have been proposed and verifed by frst-principles calculations.Tese results reveal a brand new synergistic ion migration manner and may provide up-to-date insights on the transportation process of lithium ion conductors.
