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
Metallic 1T-phase molybdenum disulfide(1T-MoS_(2))shows more excellent electrocatalytic performance for hydrogen evolution reaction(HER)than semiconducting 2H-phase MoS_(2)(2H-MoS_(2)).Therefore,the facile controllabl...Metallic 1T-phase molybdenum disulfide(1T-MoS_(2))shows more excellent electrocatalytic performance for hydrogen evolution reaction(HER)than semiconducting 2H-phase MoS_(2)(2H-MoS_(2)).Therefore,the facile controllable synthesis of hierarchical structure with rich 1T-MoS_(2)is desired for highly efficient electrocatalytic performance.In this work,a simple solvothermal method is proposed to fabricate hol-low NiCoP/MoS_(2)-V heterostructure with 63.2%1T-MoS_(2),in which the abundant catalytic active sites are exposed,the mass transfer properties are improved,and the electronic states are optimized.Moreover,the low energy difference between 2H and 1T phases and near zero free energy of hydrogen adsorption(△G H∗)result in fast kinetics and excellent catalytic performances.Specifically,the NiCoP/MoS_(2)-V com-posite exhibits enhanced HER activity with a low overpotential of 74.6 mV at 10 mA cm^(-2)and superior stability in alkaline electrolytes.This efficient design opens up new vistas for developing high-activity electrocatalysts.展开更多
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This work was financially supported by the National Natural Science Foundation of China(No.52271136)the Natural Science Foundation of Shaanxi Province(Nos.2019TD-020 and 2021JC-06)the Fundamental Scientific Research Business Expenses of Xi’an Jiaotong University(No.xzy022020017).
文摘Metallic 1T-phase molybdenum disulfide(1T-MoS_(2))shows more excellent electrocatalytic performance for hydrogen evolution reaction(HER)than semiconducting 2H-phase MoS_(2)(2H-MoS_(2)).Therefore,the facile controllable synthesis of hierarchical structure with rich 1T-MoS_(2)is desired for highly efficient electrocatalytic performance.In this work,a simple solvothermal method is proposed to fabricate hol-low NiCoP/MoS_(2)-V heterostructure with 63.2%1T-MoS_(2),in which the abundant catalytic active sites are exposed,the mass transfer properties are improved,and the electronic states are optimized.Moreover,the low energy difference between 2H and 1T phases and near zero free energy of hydrogen adsorption(△G H∗)result in fast kinetics and excellent catalytic performances.Specifically,the NiCoP/MoS_(2)-V com-posite exhibits enhanced HER activity with a low overpotential of 74.6 mV at 10 mA cm^(-2)and superior stability in alkaline electrolytes.This efficient design opens up new vistas for developing high-activity electrocatalysts.