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Lingfeng Mao - One of the best experts on this subject based on the ideXlab platform.

  • metal substitution strategy to control the Conductive Path in titanium dioxide ab initio calculations
    European Physical Journal B, 2018
    Co-Authors: Canya Zhu, Lingfeng Mao
    Abstract:

    Revealing the atomic-nature of the Conductive Path in TiO2 layer based resistive-switching devices still remains a critical challenge. Metal atoms doping in TiO2 layer are always considered as an effective way to improve the electronic properties in resistive random access memory. Efforts to clarify the effects of metal atom substitution on the Conductive Path in rutile TiO2 have been done by using first-principles calculation. The dependence of the Conductive Path on the substitution of Ag/Cu/Al/Hf/Ta/V adjacent to the ordering oxygen vacancies or away from them has been studied in detail to elucidate the formation mechanism of Conductive Path. Theoretical investigation demonstrates that Hf or V substitution where it occurs adjacent to the oxygen vacancies benefits electrons aggregation among Ti-ions. Such electrons aggregation, which is one type of the Conductive Path in TiO2, will be prompted by Ti-t2g orbital electron. The dependent relation of the Conductive Path on the substitution of Ag/Cu/Al/Hf/Ta/V will be an important factor to optimize future resistive random access memory.

  • Adsorption effect on the formation of Conductive Path in defective TiO2: ab initio calculations
    The European Physical Journal Applied Physics, 2017
    Co-Authors: Han Qin, Jianfeng Yang, Lingfeng Mao
    Abstract:

    Although the metal/TiO 2 /metal junctions providing resistive switching properties have attracted lots of attention in recent decades, revealing the atomic-nature of Conductive Path in TiO 2 active layer remains a critical challenge. Here the effects of metal adsorption on defective TiO 2 (1 1 0) surface are theoretically investigated via ab initio calculations. The dependence of the Conductive Path on the adsorption of Ti/Zr/Cu/Pt/O atoms above a lattice Ti-ion in (1 1 0) plane and at 〈1 1 0〉 direction of the defective TiO 2 (0 0 1) surface are compared. It is found that Ti adsorptions in both sites give larger contributions to the presence of Conductive Path with more stability and larger transport coefficients at Fermi level, whereas the O adsorptions at both sites fail to produce Conductive Path. Moreover, the adsorptions of Zr/Cu/Pt atoms reduce the existence possibility of Conductive Path, especially absorbed above the lattice Ti-ion at 〈1 1 0〉 direction. Thus, it is helpful to clarify the interaction of the metal electrode and oxide layer in resistive random access memory.

  • The impact of the dopants on the formation of Conductive Path in titanium dioxide: ab initio calculations
    The European Physical Journal B, 2016
    Co-Authors: Jianfeng Yang, Lingfeng Mao
    Abstract:

    Ab initio calculations are performed about the dependent characteristics of the Conductive Path on Ti/Cu/Zr interstitials and oxygen vacancies in rutile-type titanium dioxide. It is found that eight oxygen vacancies in two columns around five Ti-ions could lead to a Conductive Path. Besides, the Conductive Path will occur when additional four oxygen vacancies exist at the third column in ⟨ 110 ⟩ direction rather than on (110) facet. Oxygen vacancies at the third and fourth columns on (110) facet are considered and lead to a Conductive Path. Furthermore, one or three metal interstitials, such as Ti, Cu or Zr, are doped in titanium dioxide with three columns of oxygen vacancies on (110) facet, respectively. The Conductive Path is only found in the structure above with three Ti interstitials. We conclude that more Ti interstitials doping in reduced TiO2 benefit the formation of stable Conductive Path in resistive random access memory.

  • Conductive Path Formation by Aggregated Oxygen Ions in Titanium Dioxide: First-Principles Analyses
    Proceedings of the 2015 3rd International Conference on Machinery Materials and Information Technology Applications, 2015
    Co-Authors: Ziou Wang, Jianfeng Yang, Canyan Zhu, Lijun Zhang, Lingfeng Mao
    Abstract:

    A first-principle study on the Conductive Path formation induced by the aggregated O ions in the defected titanium dioxide (Ti12O29) is reported. The result illustrates that the O interstitials induce the aggregation of the O-ions. Thus, the formation of the Conductive Path is attributed to the continuous O-O bonds among these aggregated O-ions. In the I-V and R-V curves with the transmission coefficients, we find the resistance difference of the Pt/Ti12O29/Pt device.

Satoshi Watanabe - One of the best experts on this subject based on the ideXlab platform.

  • Conductive Path formation in the Ta₂O₅ atomic switch: first-principles analyses.
    ACS Nano, 2010
    Co-Authors: Tomofumi Tada, Satoshi Watanabe
    Abstract:

    The Conductive Path formed by the interstitial Cu or oxygen vacancies in the Ta(2)O(5) atomic switch were investigated in detail by first-principles methods. The calculated results indicated that the defect state induced by the interstitial Cu is located just at the Fermi level of the Cu and Pt electrodes in the Cu/Ta(2)O(5)/Pt heterostructure and that a conduction channel is formed in the Ta(2)O(5) film via the interstitial Cu. On the other hand, oxygen vacancies in Ta(2)O(5) do not form such a conduction channel because of the lower energy positions of their defect states. The above results suggest that the Conductive Path could be formed by interstitial Cu in the Ta(2)O(5) atomic switch, whereas the oxygen vacancies do not contribute to the formation of the Conductive Path.

  • Conductive Path formation in the ta o atomic switch first principles analyses
    ACS Nano, 2010
    Co-Authors: Tomofumi Tada, Satoshi Watanabe
    Abstract:

    The Conductive Path formed by the interstitial Cu or oxygen vacancies in the Ta(2)O(5) atomic switch were investigated in detail by first-principles methods. The calculated results indicated that the defect state induced by the interstitial Cu is located just at the Fermi level of the Cu and Pt electrodes in the Cu/Ta(2)O(5)/Pt heterostructure and that a conduction channel is formed in the Ta(2)O(5) film via the interstitial Cu. On the other hand, oxygen vacancies in Ta(2)O(5) do not form such a conduction channel because of the lower energy positions of their defect states. The above results suggest that the Conductive Path could be formed by interstitial Cu in the Ta(2)O(5) atomic switch, whereas the oxygen vacancies do not contribute to the formation of the Conductive Path.

M. Bonanomi - One of the best experts on this subject based on the ideXlab platform.

  • Transient Conductive Path induced in floating gate memories by single ions
    2005 International Conference on Integrated Circuit Design and Technology 2005. ICICDT 2005., 2005
    Co-Authors: Giorgio Cellere, Alessandro Paccagnella, Angelo Visconti, M. Bonanomi
    Abstract:

    Floating gate (FG) memory arrays were irradiated with heavy ions. After being hit by a single ion, a FG cell exhibit large threshold voltage shift due to charge loss. In particular, FGs hit by ions experience a charge loss linearly dependent on ion LET and on the electric field across the tunnel oxide. Since charge loss is by far larger than that expected from a simple generation-recombination model, we are proposing a semi-empirical model based on the idea that a Conductive Path assimilable to a resistance connects the FG to the substrate during the time (10/sup -14/s) needed for electrons to escape the tunnel oxide. The model is fully consistent with a broad range of theoretical and experimental results, and has excellent fitting capabilities.

  • transient Conductive Path induced by a single ion in 10 nm sio sub 2 layers
    IEEE Transactions on Nuclear Science, 2004
    Co-Authors: Giorgio Cellere, Alessandro Paccagnella, Angelo Visconti, M. Bonanomi, A. Candelori
    Abstract:

    Large charge loss can happen in isolated Conductive lines when hit by a single high linear energy transfer (LET) ion. We have demonstrated this phenomenon by using floating gate (FG) memory arrays, which allowed us to study it on the basis of a large statistical set of data. Charge loss is by far larger than that expected from a simple generation-recombination model. FG's hit by ions experience a charge loss linearly dependent on ion LET and on the electric field. We are proposing a semi-empirical model based on the idea that a Conductive Path assimilable to a resistance connects the FG to the substrate during the time (10/sup -14/ s) needed for electrons to escape the tunnel oxide. The model is fully consistent with a broad range of theoretical and experimental results, and has excellent fitting capabilities.

  • Transient Conductive Path induced by a Single ion in 10 nm SiO/sub 2/ Layers
    IEEE Transactions on Nuclear Science, 2004
    Co-Authors: Giorgio Cellere, Alessandro Paccagnella, Angelo Visconti, M. Bonanomi, A. Candelori
    Abstract:

    Large charge loss can happen in isolated Conductive lines when hit by a single high linear energy transfer (LET) ion. We have demonstrated this phenomenon by using floating gate (FG) memory arrays, which allowed us to study it on the basis of a large statistical set of data. Charge loss is by far larger than that expected from a simple generation-recombination model. FG's hit by ions experience a charge loss linearly dependent on ion LET and on the electric field. We are proposing a semi-empirical model based on the idea that a Conductive Path assimilable to a resistance connects the FG to the substrate during the time (10/sup -14/ s) needed for electrons to escape the tunnel oxide. The model is fully consistent with a broad range of theoretical and experimental results, and has excellent fitting capabilities.

Giorgio Cellere - One of the best experts on this subject based on the ideXlab platform.

  • Transient Conductive Path induced in floating gate memories by single ions
    2005 International Conference on Integrated Circuit Design and Technology 2005. ICICDT 2005., 2005
    Co-Authors: Giorgio Cellere, Alessandro Paccagnella, Angelo Visconti, M. Bonanomi
    Abstract:

    Floating gate (FG) memory arrays were irradiated with heavy ions. After being hit by a single ion, a FG cell exhibit large threshold voltage shift due to charge loss. In particular, FGs hit by ions experience a charge loss linearly dependent on ion LET and on the electric field across the tunnel oxide. Since charge loss is by far larger than that expected from a simple generation-recombination model, we are proposing a semi-empirical model based on the idea that a Conductive Path assimilable to a resistance connects the FG to the substrate during the time (10/sup -14/s) needed for electrons to escape the tunnel oxide. The model is fully consistent with a broad range of theoretical and experimental results, and has excellent fitting capabilities.

  • transient Conductive Path induced by a single ion in 10 nm sio sub 2 layers
    IEEE Transactions on Nuclear Science, 2004
    Co-Authors: Giorgio Cellere, Alessandro Paccagnella, Angelo Visconti, M. Bonanomi, A. Candelori
    Abstract:

    Large charge loss can happen in isolated Conductive lines when hit by a single high linear energy transfer (LET) ion. We have demonstrated this phenomenon by using floating gate (FG) memory arrays, which allowed us to study it on the basis of a large statistical set of data. Charge loss is by far larger than that expected from a simple generation-recombination model. FG's hit by ions experience a charge loss linearly dependent on ion LET and on the electric field. We are proposing a semi-empirical model based on the idea that a Conductive Path assimilable to a resistance connects the FG to the substrate during the time (10/sup -14/ s) needed for electrons to escape the tunnel oxide. The model is fully consistent with a broad range of theoretical and experimental results, and has excellent fitting capabilities.

  • Transient Conductive Path induced by a Single ion in 10 nm SiO/sub 2/ Layers
    IEEE Transactions on Nuclear Science, 2004
    Co-Authors: Giorgio Cellere, Alessandro Paccagnella, Angelo Visconti, M. Bonanomi, A. Candelori
    Abstract:

    Large charge loss can happen in isolated Conductive lines when hit by a single high linear energy transfer (LET) ion. We have demonstrated this phenomenon by using floating gate (FG) memory arrays, which allowed us to study it on the basis of a large statistical set of data. Charge loss is by far larger than that expected from a simple generation-recombination model. FG's hit by ions experience a charge loss linearly dependent on ion LET and on the electric field. We are proposing a semi-empirical model based on the idea that a Conductive Path assimilable to a resistance connects the FG to the substrate during the time (10/sup -14/ s) needed for electrons to escape the tunnel oxide. The model is fully consistent with a broad range of theoretical and experimental results, and has excellent fitting capabilities.

Jianfeng Yang - One of the best experts on this subject based on the ideXlab platform.

  • Adsorption effect on the formation of Conductive Path in defective TiO2: ab initio calculations
    The European Physical Journal Applied Physics, 2017
    Co-Authors: Han Qin, Jianfeng Yang, Lingfeng Mao
    Abstract:

    Although the metal/TiO 2 /metal junctions providing resistive switching properties have attracted lots of attention in recent decades, revealing the atomic-nature of Conductive Path in TiO 2 active layer remains a critical challenge. Here the effects of metal adsorption on defective TiO 2 (1 1 0) surface are theoretically investigated via ab initio calculations. The dependence of the Conductive Path on the adsorption of Ti/Zr/Cu/Pt/O atoms above a lattice Ti-ion in (1 1 0) plane and at 〈1 1 0〉 direction of the defective TiO 2 (0 0 1) surface are compared. It is found that Ti adsorptions in both sites give larger contributions to the presence of Conductive Path with more stability and larger transport coefficients at Fermi level, whereas the O adsorptions at both sites fail to produce Conductive Path. Moreover, the adsorptions of Zr/Cu/Pt atoms reduce the existence possibility of Conductive Path, especially absorbed above the lattice Ti-ion at 〈1 1 0〉 direction. Thus, it is helpful to clarify the interaction of the metal electrode and oxide layer in resistive random access memory.

  • The impact of the dopants on the formation of Conductive Path in titanium dioxide: ab initio calculations
    The European Physical Journal B, 2016
    Co-Authors: Jianfeng Yang, Lingfeng Mao
    Abstract:

    Ab initio calculations are performed about the dependent characteristics of the Conductive Path on Ti/Cu/Zr interstitials and oxygen vacancies in rutile-type titanium dioxide. It is found that eight oxygen vacancies in two columns around five Ti-ions could lead to a Conductive Path. Besides, the Conductive Path will occur when additional four oxygen vacancies exist at the third column in ⟨ 110 ⟩ direction rather than on (110) facet. Oxygen vacancies at the third and fourth columns on (110) facet are considered and lead to a Conductive Path. Furthermore, one or three metal interstitials, such as Ti, Cu or Zr, are doped in titanium dioxide with three columns of oxygen vacancies on (110) facet, respectively. The Conductive Path is only found in the structure above with three Ti interstitials. We conclude that more Ti interstitials doping in reduced TiO2 benefit the formation of stable Conductive Path in resistive random access memory.

  • Conductive Path Formation by Aggregated Oxygen Ions in Titanium Dioxide: First-Principles Analyses
    Proceedings of the 2015 3rd International Conference on Machinery Materials and Information Technology Applications, 2015
    Co-Authors: Ziou Wang, Jianfeng Yang, Canyan Zhu, Lijun Zhang, Lingfeng Mao
    Abstract:

    A first-principle study on the Conductive Path formation induced by the aggregated O ions in the defected titanium dioxide (Ti12O29) is reported. The result illustrates that the O interstitials induce the aggregation of the O-ions. Thus, the formation of the Conductive Path is attributed to the continuous O-O bonds among these aggregated O-ions. In the I-V and R-V curves with the transmission coefficients, we find the resistance difference of the Pt/Ti12O29/Pt device.