The present study reports the magnetizations and magneto-transport properties of PrFel_xNixO3 thin films grown by pulsed laser ablation technique on LaA103 snbstrates. From DC M/H plots of these films, weak ferromagne...The present study reports the magnetizations and magneto-transport properties of PrFel_xNixO3 thin films grown by pulsed laser ablation technique on LaA103 snbstrates. From DC M/H plots of these films, weak ferromagnetism or ferrimagnetism behaviors are observed. With Ni substitution, reduction in saturation magnetization is also seen. With Ni doping, variations in saturation field （Hs）, coercive field （Hc）, Weiss temperature （0）, and effective magnetic moment （Pelf） are seen. A small change of magnetoresitance with application of higher field is observed. Various essential parameters like density of state （Nf） at Fermi level, Mott＇s characteristic temperature （To）, and activation energy （Ea） in the presence of and in the absence of magnetic field are calculated. The present observed magnetic properties are related to the change of Fe-O bond length （causing an overlap between the oxygen p orbital and iron d orbital） and the deviation of the Fe-O-Fe angle from 180~. Reduction of magnetic domain after Ni doping is also explored to explain the present observed magnetic behavior of the system. The influence of doping on various transport properties in these thin films indicates a distortion in the lattice structure and single particle band width, owing to stress-induced reduction in unit cell volume.展开更多
Environmental pollution and the growing need to find new sources of energy are some of the challenges of our century. The unstoppable growth of population, the increasing energy needs of emerging countries, and the fo...Environmental pollution and the growing need to find new sources of energy are some of the challenges of our century. The unstoppable growth of population, the increasing energy needs of emerging countries, and the foreseeable shortage of fossil fuels in a few years, make imperative to develop new energy generation processes and, in this regard, nanotechnology and the development of new nanomaterials will play a decisive role for the future of the planet.展开更多
Quasi-type II heterostructured nanocrystals(NCs)have been of particular interest due to their great potential for controlling the interplay of charge carriers.However,the lack of material choices for quasi-type II NCs...Quasi-type II heterostructured nanocrystals(NCs)have been of particular interest due to their great potential for controlling the interplay of charge carriers.However,the lack of material choices for quasi-type II NCs restricts the accessible emission wavelength from red to near-infrared(NIR),which hinders their use in light-emitting applications that demand a wide range of visible colors.Herein,we demonstrate a new class of quasi-type II nanoemitters formulated in ZnSe/ZnSe_(1-X)Te_(X)/ZnSe seed/spherical quantum well/shell heterostructures(SQWs)whose emission wavelength ranges from blue to orange.In a given geometry,ZnSe_(1-X)Te_(X) emissive layers grown between the ZnSe seed and the shell layer are strained to fit into the surrounding media,and thus,the lattice mismatch between ZnSe_(1-X)Te_(X) and ZnSe is effectively alleviated.In addition,composition of the ZnSe_(1-X)Te_(X) emissive layer and the dimension of the ZnSe shell layer are engineered to tailor the distribution and energy of electron and hole wave functions.Benefitting from the capabilities to tune the charge carriers on demand and to form defectfree heterojunctions,ZnSe/ZnSe_(1-X)Te_(X)/ZnSe/ZnS NCs show near-unity photoluminescence quantum yield(PLQY>90%)in a broad range of emission wavelengths(peak PL from 450nm to 600 nm).Finally,we exemplify dichromatic white NC-based light-emitting diodes(NC-LEDs)employing the mixed layer of blue-and yellow-emitting ZnSe/ZnSe_(1-X)TeX/ZnSe/ZnS SQW NCs.展开更多
文摘The present study reports the magnetizations and magneto-transport properties of PrFel_xNixO3 thin films grown by pulsed laser ablation technique on LaA103 snbstrates. From DC M/H plots of these films, weak ferromagnetism or ferrimagnetism behaviors are observed. With Ni substitution, reduction in saturation magnetization is also seen. With Ni doping, variations in saturation field （Hs）, coercive field （Hc）, Weiss temperature （0）, and effective magnetic moment （Pelf） are seen. A small change of magnetoresitance with application of higher field is observed. Various essential parameters like density of state （Nf） at Fermi level, Mott＇s characteristic temperature （To）, and activation energy （Ea） in the presence of and in the absence of magnetic field are calculated. The present observed magnetic properties are related to the change of Fe-O bond length （causing an overlap between the oxygen p orbital and iron d orbital） and the deviation of the Fe-O-Fe angle from 180~. Reduction of magnetic domain after Ni doping is also explored to explain the present observed magnetic behavior of the system. The influence of doping on various transport properties in these thin films indicates a distortion in the lattice structure and single particle band width, owing to stress-induced reduction in unit cell volume.
文摘Environmental pollution and the growing need to find new sources of energy are some of the challenges of our century. The unstoppable growth of population, the increasing energy needs of emerging countries, and the foreseeable shortage of fossil fuels in a few years, make imperative to develop new energy generation processes and, in this regard, nanotechnology and the development of new nanomaterials will play a decisive role for the future of the planet.
基金the National Research Foundation of Korea(NRF)grant funded by the Ministry of Science,ICT and Future Planning(No.2020M3H4A1A01086888,No.2020M3D1A2101319,No.2020R1A2C2011478,and No.2019M3D1A1078299)the Ministry of Trade,Industry&Energy(MOTIE,Korea)(No.20010737)the Electronics and Telecommunications Research Institute(ETRI)grant funded by the Korean Government(No.20ZB1200,Development of ICT Materials,Components and Equipment Technologies).G.N.and L.A.P.are thankful for the financial support from the Sao Paulo Research Foundation(FAPESP)under the grant No.2018/15574-6.
文摘Quasi-type II heterostructured nanocrystals(NCs)have been of particular interest due to their great potential for controlling the interplay of charge carriers.However,the lack of material choices for quasi-type II NCs restricts the accessible emission wavelength from red to near-infrared(NIR),which hinders their use in light-emitting applications that demand a wide range of visible colors.Herein,we demonstrate a new class of quasi-type II nanoemitters formulated in ZnSe/ZnSe_(1-X)Te_(X)/ZnSe seed/spherical quantum well/shell heterostructures(SQWs)whose emission wavelength ranges from blue to orange.In a given geometry,ZnSe_(1-X)Te_(X) emissive layers grown between the ZnSe seed and the shell layer are strained to fit into the surrounding media,and thus,the lattice mismatch between ZnSe_(1-X)Te_(X) and ZnSe is effectively alleviated.In addition,composition of the ZnSe_(1-X)Te_(X) emissive layer and the dimension of the ZnSe shell layer are engineered to tailor the distribution and energy of electron and hole wave functions.Benefitting from the capabilities to tune the charge carriers on demand and to form defectfree heterojunctions,ZnSe/ZnSe_(1-X)Te_(X)/ZnSe/ZnS NCs show near-unity photoluminescence quantum yield(PLQY>90%)in a broad range of emission wavelengths(peak PL from 450nm to 600 nm).Finally,we exemplify dichromatic white NC-based light-emitting diodes(NC-LEDs)employing the mixed layer of blue-and yellow-emitting ZnSe/ZnSe_(1-X)TeX/ZnSe/ZnS SQW NCs.
