Polyoxometalates（POMs） with Cd-coordination complexes acting as supporting units are rarely reported. The linkage of the supporting units with inorganic building block（polyanion） is generally established on termin...Polyoxometalates（POMs） with Cd-coordination complexes acting as supporting units are rarely reported. The linkage of the supporting units with inorganic building block（polyanion） is generally established on terminal O-atoms, but scarcely via bridging O-atoms. By introducing liquid small organic molecule（pyridine, C5NH5） as assistant ＂structure-directing agent＂, we obtained a novel organic-inorganic hybrid polytungstate,（Hpy）4[Cd（phen）2（P2W18O62）]·nH2O（1, n ≈ 3, py = pyridine, phen = 1,10-phenanthroline）, under hydrothermal conditions. The single-crystal X-ray diffraction analysis shows that 1 is the first compound containing an asymmetric heteropolyanion, [Cd（phen）2（P2W18O62）]4–, a Wells-Dawson-type polyanion monosupported by Cd-coordination complex via di-bridging O-atoms.展开更多
Chemical and field-effect passivation of atomic layer deposition （ALD） Al2O3 films are investigated, mainly by corona charging measurement. The interface structure and material properties are characterized by transm...Chemical and field-effect passivation of atomic layer deposition （ALD） Al2O3 films are investigated, mainly by corona charging measurement. The interface structure and material properties are characterized by transmission electron microscopy （TEM） and X-ray photoelectron spectroscopy （XPS）, respectively. Passivation performance is improved remarkably by annealing at temperatures of 450 ℃ and 500 ℃, while the improvement is quite weak at 600 ℃, which can be attributed to the poor quality of chemical passivation. An increase of fixed negative charge density in the films during annealing can be explained by the Al2O3/Si interface structural change. The Al–OH groups play an important role in chemical passivation, and the Al–OH concentration in an as-deposited film subsequently determines the passivation quality of that film when it is annealed, to a certain degree.展开更多
Amorphous indium-gallium-zinc oxide(a-IGZO)thin films are prepared by pulsed laser deposition and fabricated into thin-film transistor(TFT)devices.In-situ x-ray photoelectron spectroscopy(XPS)illustrates that weakly b...Amorphous indium-gallium-zinc oxide(a-IGZO)thin films are prepared by pulsed laser deposition and fabricated into thin-film transistor(TFT)devices.In-situ x-ray photoelectron spectroscopy(XPS)illustrates that weakly bonded oxygen(O)atoms exist in a-IGZO thin films deposited at high O_(2) pressures,but these can be eliminated by vacuum annealing.The threshold voltage(V_(th))of the a-IGZO TFTs is shifted under positive gate bias,and the Vth shift is positively related to the deposition pressure.A temperature variation experiment in the range of 20 K-300 K demonstrates that an activation energy of 144 meV is required for the Vth shift,which is close to the activation energy required for the migration of weakly bonded O atoms in a-IGZO thin films.Accordingly,the Vth shift is attributed to the acceptor-like states induced by the accumulation of weakly bonded O atoms at the a-IGZO/SiO_(2) interface under positive gate bias.These results provide an insight into the mechanism responsible for the Vth shift of the a-IGZO TFTs and help in the production of reliable designs.展开更多
Aliphatic amine N-oxides, particularly （CH<sub>3</sub>）<sub>3</sub>NO, have been widely used as O-atom transfer reagents in organometallic chemistry. Recently the systematic kinetic studies o...Aliphatic amine N-oxides, particularly （CH<sub>3</sub>）<sub>3</sub>NO, have been widely used as O-atom transfer reagents in organometallic chemistry. Recently the systematic kinetic studies on O-atom transfer reactions have been reported in detail. However, little is known about the use of pyridine N-oxides and the related aromatic amine N-oxides as O-atom transfer reagents in organometallic chemistry, and no kinetic or展开更多
OH radicals and O atoms are two of the most important reactive species of non-equilibrium atmospheric pressure plasma(NAPP),which plays an important role in applications such as plasma medicine.However,experimental st...OH radicals and O atoms are two of the most important reactive species of non-equilibrium atmospheric pressure plasma(NAPP),which plays an important role in applications such as plasma medicine.However,experimental studies on how the gas content affects the postdischarge temporal evolutions of OH and O in the noble gas ns-NAPP are very limited.In this work,the effect of the percentages of O_(2),N_(2),and H_(2)O on the amounts of OH and O productions and their post-discharge temporal behaviors in ns-NAPP is investigated by laser-induced fluorescence(LIF)method.The results show that the productions of OH and O increase and then decrease with the increase of O_(2)percentage.Both OH and O densities reach their maximum when about 0.8%O_(2)is added.Further increase of the O_(2)concentration results in a decrease of the initial densities of both OH and O,and leads to their faster decay.The increase of N_(2)percentage also results in the increase and then decrease of the OH and O densities,but the change is smaller.Furthermore,when the H_(2)O concentration is increased from 100 to 3000 ppm,the initial OH density increases slightly,but the OH density decays much faster,while the initial density of O decreases with the increase of the H_(2)O concentration.After analysis,it is found that OH and O are mainly produced through electron collisional dissociation.O(^(1)D)is critical for OH generation.O_(3)accelerates the consumption processes of OH and O at high O_(2)percentage.The addition of H_(2)O in the NAPP considerably enhances the electronegativity,while it decreases the overall plasma reactivity,accelerates the decay of OH,and reduces the O atom density.展开更多
基金supported by the Foundation of Education Department of Fujian Province(Nos.JB12199 and JA11245)the National Natural Science Foundation of China(Nos.21233004 and 40972035)
文摘Polyoxometalates（POMs） with Cd-coordination complexes acting as supporting units are rarely reported. The linkage of the supporting units with inorganic building block（polyanion） is generally established on terminal O-atoms, but scarcely via bridging O-atoms. By introducing liquid small organic molecule（pyridine, C5NH5） as assistant ＂structure-directing agent＂, we obtained a novel organic-inorganic hybrid polytungstate,（Hpy）4[Cd（phen）2（P2W18O62）]·nH2O（1, n ≈ 3, py = pyridine, phen = 1,10-phenanthroline）, under hydrothermal conditions. The single-crystal X-ray diffraction analysis shows that 1 is the first compound containing an asymmetric heteropolyanion, [Cd（phen）2（P2W18O62）]4–, a Wells-Dawson-type polyanion monosupported by Cd-coordination complex via di-bridging O-atoms.
基金Project supported by the National Natural Science Foundation of China(Grant No.61106060)the Knowledge Innovation Program of the Chinese Academy of Sciences(Grant No.Y2YF028001)the National High Technology Research and Development Program of China(Grant No.2012AA052401)
文摘Chemical and field-effect passivation of atomic layer deposition （ALD） Al2O3 films are investigated, mainly by corona charging measurement. The interface structure and material properties are characterized by transmission electron microscopy （TEM） and X-ray photoelectron spectroscopy （XPS）, respectively. Passivation performance is improved remarkably by annealing at temperatures of 450 ℃ and 500 ℃, while the improvement is quite weak at 600 ℃, which can be attributed to the poor quality of chemical passivation. An increase of fixed negative charge density in the films during annealing can be explained by the Al2O3/Si interface structural change. The Al–OH groups play an important role in chemical passivation, and the Al–OH concentration in an as-deposited film subsequently determines the passivation quality of that film when it is annealed, to a certain degree.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51771144 and 62104189)the Natural Science Foundation of Shaanxi Province,China(Grant Nos.2021JC-06,2019TD-020,and 2019JLM-30)+1 种基金the China Postdoctoral Science Foundation(Grant No.2020M683483)the Fundamental scientific research business expenses of Xi'an Jiaotong University(Grant No.XZY022020017).
文摘Amorphous indium-gallium-zinc oxide(a-IGZO)thin films are prepared by pulsed laser deposition and fabricated into thin-film transistor(TFT)devices.In-situ x-ray photoelectron spectroscopy(XPS)illustrates that weakly bonded oxygen(O)atoms exist in a-IGZO thin films deposited at high O_(2) pressures,but these can be eliminated by vacuum annealing.The threshold voltage(V_(th))of the a-IGZO TFTs is shifted under positive gate bias,and the Vth shift is positively related to the deposition pressure.A temperature variation experiment in the range of 20 K-300 K demonstrates that an activation energy of 144 meV is required for the Vth shift,which is close to the activation energy required for the migration of weakly bonded O atoms in a-IGZO thin films.Accordingly,the Vth shift is attributed to the acceptor-like states induced by the accumulation of weakly bonded O atoms at the a-IGZO/SiO_(2) interface under positive gate bias.These results provide an insight into the mechanism responsible for the Vth shift of the a-IGZO TFTs and help in the production of reliable designs.
基金Project supported by the National Natural Science Foundation of China
文摘Aliphatic amine N-oxides, particularly （CH<sub>3</sub>）<sub>3</sub>NO, have been widely used as O-atom transfer reagents in organometallic chemistry. Recently the systematic kinetic studies on O-atom transfer reactions have been reported in detail. However, little is known about the use of pyridine N-oxides and the related aromatic amine N-oxides as O-atom transfer reagents in organometallic chemistry, and no kinetic or
基金supported by National Natural Science Foundation of China(Nos.52130701 and 51977096)the National Key Research and Development Program of China(No.2021YFE0114700)。
文摘OH radicals and O atoms are two of the most important reactive species of non-equilibrium atmospheric pressure plasma(NAPP),which plays an important role in applications such as plasma medicine.However,experimental studies on how the gas content affects the postdischarge temporal evolutions of OH and O in the noble gas ns-NAPP are very limited.In this work,the effect of the percentages of O_(2),N_(2),and H_(2)O on the amounts of OH and O productions and their post-discharge temporal behaviors in ns-NAPP is investigated by laser-induced fluorescence(LIF)method.The results show that the productions of OH and O increase and then decrease with the increase of O_(2)percentage.Both OH and O densities reach their maximum when about 0.8%O_(2)is added.Further increase of the O_(2)concentration results in a decrease of the initial densities of both OH and O,and leads to their faster decay.The increase of N_(2)percentage also results in the increase and then decrease of the OH and O densities,but the change is smaller.Furthermore,when the H_(2)O concentration is increased from 100 to 3000 ppm,the initial OH density increases slightly,but the OH density decays much faster,while the initial density of O decreases with the increase of the H_(2)O concentration.After analysis,it is found that OH and O are mainly produced through electron collisional dissociation.O(^(1)D)is critical for OH generation.O_(3)accelerates the consumption processes of OH and O at high O_(2)percentage.The addition of H_(2)O in the NAPP considerably enhances the electronegativity,while it decreases the overall plasma reactivity,accelerates the decay of OH,and reduces the O atom density.
