Thecorrelation between composition, structure, chemical bond, and thermoelectric proper tiesof Si doped boroncarbidesisstudied using SCF DV Xαmethod. Thecalculationsshow that Siatom firstlysubstitutes Bor Catomson th...Thecorrelation between composition, structure, chemical bond, and thermoelectric proper tiesof Si doped boroncarbidesisstudied using SCF DV Xαmethod. Thecalculationsshow that Siatom firstlysubstitutes Bor Catomson theend of boron carbidechain, then may occupyinterstitialsites when Siis dopedin boron carbide, anditisdifficultfor SitosubstituteBor Catom in thecenter of chain orintheicosahedron. Arepresentativestructural unitcontain ing an Si atom is 〔C B Si〕ε+ 〔B11 C〕ε , whilethe structural unit without Siis 〔C B B ( C)〕δ 〔B11 C〕δ+ . Afteradding Sitotheboroncarbides,theenergyrequired bythe dispro portionation reaction decreases,theconcentrationofthecarriersincreases,andthereare more pathsfor the bipolaron to hopping. At thesametime, the covalent bond becomes weaker, andthethermal conductivity decreases. Therefore, thethermoelectric property of Si dopedboron carbidesisimproved .展开更多
The thermodynamic properties of Cu-Ce-S and Cu-Y-S liquid solutions were studied by the chemical equilibrium technique at 1200℃. The equilibrium constants and the standard free energies of formation of CeS and YS wer...The thermodynamic properties of Cu-Ce-S and Cu-Y-S liquid solutions were studied by the chemical equilibrium technique at 1200℃. The equilibrium constants and the standard free energies of formation of CeS and YS were determined for the reactions: CeS=[Ce]+[S] and YS = [Y]+[S] . For the solution of Ce_(1) and Y_(l) in pure Cu according to the reactions: Ce_(1)= [Ce] and Y_(1)= [Y] , the standard free energies of solutions were obtained. The first order and second order interaction coefficients between solute elements as well as the activity coefficients γ_(Ce)~0 and γ_Y^0 in liquid Cu were also determined.展开更多
Sr_(0.5)Ca_(0.5)CuO_2 has been synthesized by the solid state reaction.The compound crystallizes in an orthorhombic unit cell,space group D_(2h)^(17)-Cmcm with a=3.444 ,b=16.11 ,c=3.868 .It decomposes shove 1038℃. ...Sr_(0.5)Ca_(0.5)CuO_2 has been synthesized by the solid state reaction.The compound crystallizes in an orthorhombic unit cell,space group D_(2h)^(17)-Cmcm with a=3.444 ,b=16.11 ,c=3.868 .It decomposes shove 1038℃. Sr_(0.5)Ca_(0.5)CuO_2 is s black p-type semiconductor with resistivity 53Ω.cm at room tempersture.展开更多
In this work,the electrical property of Au/graphene oxide/p-InP hetero-structure has been evaluated by 1-V and C-V measure-ments in dark and iluminated conditions(visible light).The diode exhibited significant rectify...In this work,the electrical property of Au/graphene oxide/p-InP hetero-structure has been evaluated by 1-V and C-V measure-ments in dark and iluminated conditions(visible light).The diode exhibited significant rectifying behavior,thus indicating the heterojunction-lype diode.The key electrical parameters of heterojunction diode including ideality factor(n),series resistance(R),shunt resistance(Rsh),and barrier height(Фb)are estimated from I-V data based on the theory of thermionic emission.The modifed Norde and Cheung's methods were utilized to evaluate the electrical parameters and compared the results.The current conduction mechanism at different voltage regions of I-V has also been investigated.The variation of 1/C versus voltage signifies linearity at high frequency(1 MHz),indicating that the type of heterojunction can be abrupt.The experimental outcomes of this study revealed that the performance of heterojunction diode in dark is considerably good as compared to the ilumination condition with respect to the lower values of Фp,n,R,and interface state density(Nss).展开更多
文摘Thecorrelation between composition, structure, chemical bond, and thermoelectric proper tiesof Si doped boroncarbidesisstudied using SCF DV Xαmethod. Thecalculationsshow that Siatom firstlysubstitutes Bor Catomson theend of boron carbidechain, then may occupyinterstitialsites when Siis dopedin boron carbide, anditisdifficultfor SitosubstituteBor Catom in thecenter of chain orintheicosahedron. Arepresentativestructural unitcontain ing an Si atom is 〔C B Si〕ε+ 〔B11 C〕ε , whilethe structural unit without Siis 〔C B B ( C)〕δ 〔B11 C〕δ+ . Afteradding Sitotheboroncarbides,theenergyrequired bythe dispro portionation reaction decreases,theconcentrationofthecarriersincreases,andthereare more pathsfor the bipolaron to hopping. At thesametime, the covalent bond becomes weaker, andthethermal conductivity decreases. Therefore, thethermoelectric property of Si dopedboron carbidesisimproved .
文摘The thermodynamic properties of Cu-Ce-S and Cu-Y-S liquid solutions were studied by the chemical equilibrium technique at 1200℃. The equilibrium constants and the standard free energies of formation of CeS and YS were determined for the reactions: CeS=[Ce]+[S] and YS = [Y]+[S] . For the solution of Ce_(1) and Y_(l) in pure Cu according to the reactions: Ce_(1)= [Ce] and Y_(1)= [Y] , the standard free energies of solutions were obtained. The first order and second order interaction coefficients between solute elements as well as the activity coefficients γ_(Ce)~0 and γ_Y^0 in liquid Cu were also determined.
文摘Sr_(0.5)Ca_(0.5)CuO_2 has been synthesized by the solid state reaction.The compound crystallizes in an orthorhombic unit cell,space group D_(2h)^(17)-Cmcm with a=3.444 ,b=16.11 ,c=3.868 .It decomposes shove 1038℃. Sr_(0.5)Ca_(0.5)CuO_2 is s black p-type semiconductor with resistivity 53Ω.cm at room tempersture.
基金The authors would like to thank the National Science Fund for Excellent Young Scholars(51722509)National Key Research and Development Program of China(2017YFB1104700)+1 种基金Program for Science and Technology Innovation Group of Shaanxi Province(2019TD-011)Key Research and Development Program of Shaanxi Province(2020ZDLGY04-02)for support.
文摘In this work,the electrical property of Au/graphene oxide/p-InP hetero-structure has been evaluated by 1-V and C-V measure-ments in dark and iluminated conditions(visible light).The diode exhibited significant rectifying behavior,thus indicating the heterojunction-lype diode.The key electrical parameters of heterojunction diode including ideality factor(n),series resistance(R),shunt resistance(Rsh),and barrier height(Фb)are estimated from I-V data based on the theory of thermionic emission.The modifed Norde and Cheung's methods were utilized to evaluate the electrical parameters and compared the results.The current conduction mechanism at different voltage regions of I-V has also been investigated.The variation of 1/C versus voltage signifies linearity at high frequency(1 MHz),indicating that the type of heterojunction can be abrupt.The experimental outcomes of this study revealed that the performance of heterojunction diode in dark is considerably good as compared to the ilumination condition with respect to the lower values of Фp,n,R,and interface state density(Nss).
