In the quest to enhance the efficiency of sodium-ion batteries,the dynamics of solid electrolyte interphase(SEI)formation are of paramount importance.The SEI layer’s integrity is integral to the charge–discharge eff...In the quest to enhance the efficiency of sodium-ion batteries,the dynamics of solid electrolyte interphase(SEI)formation are of paramount importance.The SEI layer’s integrity is integral to the charge–discharge efficiency and the overall longevity of the battery.Herein,a novel two-dimensional Ti_(3)C_(2) fragments enmeshed on iron-nitrogen-carbon(Fe-N-C)nanosheets(Ti_(3)C_(2)/Fe-NC)has been synthesized.This electrode features a matrix which has been shown to expedite SEI layer formation through the facilitation of selective anion adsorption,thus augmenting battery performance.Density functional theory calculation reveals that the SEI evolution energy of NaPF6 at the Ti_(3)C_(2)/Fe-N-C interface is 0.81 eV,significantly lower than the Ti_(3)C_(2)(1.23 eV).This process is driven by the electron transportation from Ti_(3)C_(2) to Fe-N-C substrate,facilitated by their work-function difference,leading to the formation of ferromagnetic Fe species,which possesses Fe 3d d_(xz)d_(z)2 orbitals and undergoes hybridization with theπandσorbitals of NaF,creating a key intermediate during charging.This process diminishes the antibonding energy and attenuates the orbital interaction with NaF,thus reducing the activation energy and improving the SEI formation reaction kinetics.Consequently,it leads to the creation of multi-interface SEI characterized by high-throughput ion transport and an efficient reaction network.展开更多
We evaluated the TiN/TaN/TiA1 triple-layer to modulate the effective work function （EWF） of a metal gate stack for the n-type metal-oxide-semiconductor （NMOS） devices application by varying the TiN/TaN thickness. ...We evaluated the TiN/TaN/TiA1 triple-layer to modulate the effective work function （EWF） of a metal gate stack for the n-type metal-oxide-semiconductor （NMOS） devices application by varying the TiN/TaN thickness. In this paper, the effective work function of EWF ranges from 4.22 to 4.56 eV with different thicknesses of TiN and TaN. The thinner TiN and/or thinner in situ TaN capping, the closer to conduction band of silicon the EWF is, which is appropriate for 2-D planar NMOS. Mid-gap work function behavior is observed with thicker TiN, thicker in situ TaN capping, indicating a strong potential candidate of metal gate material for replacement gate processed three-dimensional devices such as FIN shaped field effect transistors. The physical understandings of the sensitivity of EWF to TiN and TaN thickness are proposed. The thicker TiN prevents the A1 diffusion then induces the EWF to shift to mid-gap. However, the TaN plays a different role in effective work function tuning from TiN, due to the Ta-O dipoles formed at the interface between the metal gate and the high-k layer.展开更多
金属功函数波动作为器件制造过程中的主要工艺波动源之一,其波动变化对器件电学特性有极大的影响。本文提出一种简便、快速预测半导体场效应管金属功函数波动效应的方法,并将其与商业软件中计算功函数波动的统计阻抗场法进行对比分析。...金属功函数波动作为器件制造过程中的主要工艺波动源之一,其波动变化对器件电学特性有极大的影响。本文提出一种简便、快速预测半导体场效应管金属功函数波动效应的方法,并将其与商业软件中计算功函数波动的统计阻抗场法进行对比分析。参考IBM公司发布的14 nm SOI FinFET结构建立FinFET器件仿真模型并与实验数据对比验证后,引入金属功函数波动,分别用统计阻抗场法与本文提出的快速预测方法计算得到对应随机波动下模型的阈值电压V_(th)、关断电流I_(off)、工作电流I_(on)等电学特性参数的随机分布及这些参数结果的期望值、标准差、极差等统计参数,通过两者结果对比验证了快速预测方法的准确性。展开更多
基金supported by the National Natural Science Foundation of China(Nos.U22A20107,22162026,and 42050203)the Science and Technology Research and Develpoment Program Joint Fund Project of Henan Provincial(No.222301420001)+3 种基金the Distinguished Young Scholars Innovation Team of Zhengzhou University(No.32320275)Key Research Projects of University in Henan Province(No.24A150041)Henan Province Science and Technology Research Projects(No.242102240106)Postdoctoral Fellowship Program of CPSF(No.GZC20232382).
文摘In the quest to enhance the efficiency of sodium-ion batteries,the dynamics of solid electrolyte interphase(SEI)formation are of paramount importance.The SEI layer’s integrity is integral to the charge–discharge efficiency and the overall longevity of the battery.Herein,a novel two-dimensional Ti_(3)C_(2) fragments enmeshed on iron-nitrogen-carbon(Fe-N-C)nanosheets(Ti_(3)C_(2)/Fe-NC)has been synthesized.This electrode features a matrix which has been shown to expedite SEI layer formation through the facilitation of selective anion adsorption,thus augmenting battery performance.Density functional theory calculation reveals that the SEI evolution energy of NaPF6 at the Ti_(3)C_(2)/Fe-N-C interface is 0.81 eV,significantly lower than the Ti_(3)C_(2)(1.23 eV).This process is driven by the electron transportation from Ti_(3)C_(2) to Fe-N-C substrate,facilitated by their work-function difference,leading to the formation of ferromagnetic Fe species,which possesses Fe 3d d_(xz)d_(z)2 orbitals and undergoes hybridization with theπandσorbitals of NaF,creating a key intermediate during charging.This process diminishes the antibonding energy and attenuates the orbital interaction with NaF,thus reducing the activation energy and improving the SEI formation reaction kinetics.Consequently,it leads to the creation of multi-interface SEI characterized by high-throughput ion transport and an efficient reaction network.
基金Project supported by the Important National Science & Technology Specific Projects(No.2009ZX02035)the National Natural Science Foundation of China(Nos.61176091,61306129)
文摘We evaluated the TiN/TaN/TiA1 triple-layer to modulate the effective work function （EWF） of a metal gate stack for the n-type metal-oxide-semiconductor （NMOS） devices application by varying the TiN/TaN thickness. In this paper, the effective work function of EWF ranges from 4.22 to 4.56 eV with different thicknesses of TiN and TaN. The thinner TiN and/or thinner in situ TaN capping, the closer to conduction band of silicon the EWF is, which is appropriate for 2-D planar NMOS. Mid-gap work function behavior is observed with thicker TiN, thicker in situ TaN capping, indicating a strong potential candidate of metal gate material for replacement gate processed three-dimensional devices such as FIN shaped field effect transistors. The physical understandings of the sensitivity of EWF to TiN and TaN thickness are proposed. The thicker TiN prevents the A1 diffusion then induces the EWF to shift to mid-gap. However, the TaN plays a different role in effective work function tuning from TiN, due to the Ta-O dipoles formed at the interface between the metal gate and the high-k layer.
文摘金属功函数波动作为器件制造过程中的主要工艺波动源之一,其波动变化对器件电学特性有极大的影响。本文提出一种简便、快速预测半导体场效应管金属功函数波动效应的方法,并将其与商业软件中计算功函数波动的统计阻抗场法进行对比分析。参考IBM公司发布的14 nm SOI FinFET结构建立FinFET器件仿真模型并与实验数据对比验证后,引入金属功函数波动,分别用统计阻抗场法与本文提出的快速预测方法计算得到对应随机波动下模型的阈值电压V_(th)、关断电流I_(off)、工作电流I_(on)等电学特性参数的随机分布及这些参数结果的期望值、标准差、极差等统计参数,通过两者结果对比验证了快速预测方法的准确性。
