The Experts below are selected from a list of 14985 Experts worldwide ranked by ideXlab platform
Joseph T Hupp - One of the best experts on this subject based on the ideXlab platform.
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Atomistic Approach toward selective photocatalytic oxidation of a mustard gas simulant a case study with heavy chalcogen containing pcn 57 analogues
ACS Applied Materials & Interfaces, 2017Co-Authors: Subhadip Goswami, Claire E. Miller, Jenna L. Logsdon, Cassandra T. Buru, David N. Bowman, Timur Islamoglu, Abdullah M. Asiri, Christopher J. Cramer, Michael R. Wasielewski, Joseph T HuppAbstract:Here we describe the synthesis of two Zr-based benzothiadiazole- and benzoselenadiazole-containing metal–organic frameworks (MOFs) for the selective photocatalytic oxidation of the mustard gas simulant, 2-chloroethyl ethyl sulfide (CEES). The photophysical properties of the linkers and MOFs are characterized by steady-state absorption and emission, time-resolved emission, and ultrafast transient absorption spectroscopy. The benzoselenadiazole-containing MOF shows superior catalytic activity compared to that containing benzothiadiazole with a half-life of 3.5 min for CEES oxidation to nontoxic 2-chloroethyl ethyl sulfoxide (CEESO). Transient absorption spectroscopy performed on the benzoselenadiazole linker reveals the presence of a triplet excited state, which decays with a lifetime of 9.4 μs, resulting in the generation of singlet oxygen for photocatalysis. This study demonstrates the effect of heavy chalcogen substitution within a porous framework for the modulation of photocatalytic activity.
Subhadip Goswami - One of the best experts on this subject based on the ideXlab platform.
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Atomistic Approach toward selective photocatalytic oxidation of a mustard gas simulant a case study with heavy chalcogen containing pcn 57 analogues
ACS Applied Materials & Interfaces, 2017Co-Authors: Subhadip Goswami, Claire E. Miller, Jenna L. Logsdon, Cassandra T. Buru, David N. Bowman, Timur Islamoglu, Abdullah M. Asiri, Christopher J. Cramer, Michael R. Wasielewski, Joseph T HuppAbstract:Here we describe the synthesis of two Zr-based benzothiadiazole- and benzoselenadiazole-containing metal–organic frameworks (MOFs) for the selective photocatalytic oxidation of the mustard gas simulant, 2-chloroethyl ethyl sulfide (CEES). The photophysical properties of the linkers and MOFs are characterized by steady-state absorption and emission, time-resolved emission, and ultrafast transient absorption spectroscopy. The benzoselenadiazole-containing MOF shows superior catalytic activity compared to that containing benzothiadiazole with a half-life of 3.5 min for CEES oxidation to nontoxic 2-chloroethyl ethyl sulfoxide (CEESO). Transient absorption spectroscopy performed on the benzoselenadiazole linker reveals the presence of a triplet excited state, which decays with a lifetime of 9.4 μs, resulting in the generation of singlet oxygen for photocatalysis. This study demonstrates the effect of heavy chalcogen substitution within a porous framework for the modulation of photocatalytic activity.
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Atomistic Approach toward Selective Photocatalytic Oxidation of a Mustard-Gas Simulant: A Case Study with Heavy-Chalcogen-Containing PCN-57 Analogues
2017Co-Authors: Subhadip Goswami, Claire E. Miller, Jenna L. Logsdon, Cassandra T. Buru, David N. Bowman, Timur Islamoglu, Abdullah M. Asiri, Christopher J. Cramer, Michael R. WasielewskiAbstract:Here we describe the synthesis of two Zr-based benzothiadiazole- and benzoselenadiazole-containing metal–organic frameworks (MOFs) for the selective photocatalytic oxidation of the mustard gas simulant, 2-chloroethyl ethyl sulfide (CEES). The photophysical properties of the linkers and MOFs are characterized by steady-state absorption and emission, time-resolved emission, and ultrafast transient absorption spectroscopy. The benzoselenadiazole-containing MOF shows superior catalytic activity compared to that containing benzothiadiazole with a half-life of 3.5 min for CEES oxidation to nontoxic 2-chloroethyl ethyl sulfoxide (CEESO). Transient absorption spectroscopy performed on the benzoselenadiazole linker reveals the presence of a triplet excited state, which decays with a lifetime of 9.4 μs, resulting in the generation of singlet oxygen for photocatalysis. This study demonstrates the effect of heavy chalcogen substitution within a porous framework for the modulation of photocatalytic activity
Joerg Appenzeller - One of the best experts on this subject based on the ideXlab platform.
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a predictive analytic model for high performance tunneling field effect transistors Approaching non equilibrium green s function simulations
Journal of Applied Physics, 2015Co-Authors: R Salazar, Rajib Rahman, Gerhard Klimeck, Hesameddin Ilatikhameneh, Joerg AppenzellerAbstract:A new compact modeling Approach is presented which describes the full current-voltage (I-V) characteristic of high-performance (aggressively scaled-down) tunneling field-effect-transistors (TFETs) based on homojunction direct-bandgap semiconductors. The model is based on an analytic description of two key features, which capture the main physical phenomena related to TFETs: (1) the potential profile from source to channel and (2) the elliptic curvature of the complex bands in the bandgap region. It is proposed to use 1D Poisson's equations in the source and the channel to describe the potential profile in homojunction TFETs. This allows to quantify the impact of source/drain doping on device performance, an aspect usually ignored in TFET modeling but highly relevant in ultra-scaled devices. The compact model is validated by comparison with state-of-the-art quantum transport simulations using a 3D full band Atomistic Approach based on non-equilibrium Green's functions. It is shown that the model reproduces with good accuracy the data obtained from the simulations in all regions of operation: the on/off states and the n/p branches of conduction. This Approach allows calculation of energy-dependent band-to-band tunneling currents in TFETs, a feature that allows gaining deep insights into the underlying device physics. The simplicity and accuracy of the Approach provide a powerful tool to explore in a quantitatively manner how a wide variety of parameters (material-, size-, and/or geometry-dependent) impact the TFET performance under any bias conditions. The proposed model presents thus a practical complement to computationally expensive simulations such as the 3D NEGF Approach.
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a predictive analytic model for high performance tunneling field effect transistors Approaching non equilibrium green s function simulations
arXiv: Mesoscale and Nanoscale Physics, 2015Co-Authors: R Salazar, Rajib Rahman, Gerhard Klimeck, Hesameddin Ilatikhameneh, Joerg AppenzellerAbstract:A new compact modeling Approach is presented which describes the full current-voltage (I-V) characteristic of high-performance (aggressively scaled-down) tunneling field-effect-transistors (TFETs) based on homojunction direct-bandgap semiconductors. The model is based on an analytic description of two key features, which capture the main physical phenomena related to TFETs: 1) the potential profile from source to channel, and 2) the elliptic curvature of the complex bands in the bandgap region. It is proposed to use 1D Poisson's equations in the source and the channel to describe the potential profile in homojunction TFETs. This allows to quantify the impact of source/drain doping on device performance, an aspect usually ignored in TFET modeling but highly relevant in ultra-scaled devices. The compact model is validated by comparison with state-of-the-art quantum transport simulations using a 3D full band Atomistic Approach based on Non-Equilibrium Green's Functions (NEGF). It is shown that the model reproduces with good accuracy the data obtained from the simulations in all regions of operation: the on/off states and the n/p branches of conduction. This Approach allows calculation of energy-dependent band-toband tunneling currents in TFETs, a feature that allows gaining deep insights into the underlying device physics. The simplicity and accuracy of the Approach provides a powerful tool to explore in a quantitatively manner how a wide variety of parameters (material-, size- and/or geometrydependent) impact the TFET performance under any bias conditions. The proposed model presents thus a practical complement to computationally expensive simulations such as the 3D NEGF Approach.
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a predictive compact model for high performance tunneling field effect transistors Approaching the accuracy of negf simulations
arXiv: Mesoscale and Nanoscale Physics, 2015Co-Authors: R Salazar, Rajib Rahman, Gerhard Klimeck, Hesameddin Ilatikhameneh, Joerg AppenzellerAbstract:A new compact modeling Approach is presented which describes the full current-voltage (I-V) characteristic of high-performance (aggressively scaled-down) tunneling field-effect-transistors (TFETs) based on homojunction direct-bandgap semiconductors. The model is based on an analytic description of two key features, which capture the main physical phenomena related to TFETs: 1) the potential profile from source to channel, and 2) the elliptic curvature of the complex bands in the bandgap region. It is proposed to use 1D Poisson's equations in the source and the channel to describe the potential profile in homojunction TFETs. This allows to quantify the impact of source/drain doping on device performance, an aspect usually ignored in TFET modeling but highly relevant in ultra-scaled devices. The compact model is validated by comparison with state-of-the-art quantum transport simulations using a 3D full band Atomistic Approach based on Non-Equilibrium Green's Functions (NEGF). It is shown that the model reproduces with good accuracy the data obtained from the simulations in all regions of operation: the on/off states and the n/p branches of conduction. This Approach allows calculation of energy-dependent band-toband tunneling currents in TFETs, a feature that allows gaining deep insights into the underlying device physics. The simplicity and accuracy of the Approach provides a powerful tool to explore in a quantitatively manner how a wide variety of parameters (material-, size- and/or geometrydependent) impact the TFET performance under any bias conditions. The proposed model presents thus a practical complement to computationally expensive simulations such as the 3D NEGF Approach.
Michael R. Wasielewski - One of the best experts on this subject based on the ideXlab platform.
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Atomistic Approach toward selective photocatalytic oxidation of a mustard gas simulant a case study with heavy chalcogen containing pcn 57 analogues
ACS Applied Materials & Interfaces, 2017Co-Authors: Subhadip Goswami, Claire E. Miller, Jenna L. Logsdon, Cassandra T. Buru, David N. Bowman, Timur Islamoglu, Abdullah M. Asiri, Christopher J. Cramer, Michael R. Wasielewski, Joseph T HuppAbstract:Here we describe the synthesis of two Zr-based benzothiadiazole- and benzoselenadiazole-containing metal–organic frameworks (MOFs) for the selective photocatalytic oxidation of the mustard gas simulant, 2-chloroethyl ethyl sulfide (CEES). The photophysical properties of the linkers and MOFs are characterized by steady-state absorption and emission, time-resolved emission, and ultrafast transient absorption spectroscopy. The benzoselenadiazole-containing MOF shows superior catalytic activity compared to that containing benzothiadiazole with a half-life of 3.5 min for CEES oxidation to nontoxic 2-chloroethyl ethyl sulfoxide (CEESO). Transient absorption spectroscopy performed on the benzoselenadiazole linker reveals the presence of a triplet excited state, which decays with a lifetime of 9.4 μs, resulting in the generation of singlet oxygen for photocatalysis. This study demonstrates the effect of heavy chalcogen substitution within a porous framework for the modulation of photocatalytic activity.
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Atomistic Approach toward Selective Photocatalytic Oxidation of a Mustard-Gas Simulant: A Case Study with Heavy-Chalcogen-Containing PCN-57 Analogues
2017Co-Authors: Subhadip Goswami, Claire E. Miller, Jenna L. Logsdon, Cassandra T. Buru, David N. Bowman, Timur Islamoglu, Abdullah M. Asiri, Christopher J. Cramer, Michael R. WasielewskiAbstract:Here we describe the synthesis of two Zr-based benzothiadiazole- and benzoselenadiazole-containing metal–organic frameworks (MOFs) for the selective photocatalytic oxidation of the mustard gas simulant, 2-chloroethyl ethyl sulfide (CEES). The photophysical properties of the linkers and MOFs are characterized by steady-state absorption and emission, time-resolved emission, and ultrafast transient absorption spectroscopy. The benzoselenadiazole-containing MOF shows superior catalytic activity compared to that containing benzothiadiazole with a half-life of 3.5 min for CEES oxidation to nontoxic 2-chloroethyl ethyl sulfoxide (CEESO). Transient absorption spectroscopy performed on the benzoselenadiazole linker reveals the presence of a triplet excited state, which decays with a lifetime of 9.4 μs, resulting in the generation of singlet oxygen for photocatalysis. This study demonstrates the effect of heavy chalcogen substitution within a porous framework for the modulation of photocatalytic activity
Gerhard Klimeck - One of the best experts on this subject based on the ideXlab platform.
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a predictive analytic model for high performance tunneling field effect transistors Approaching non equilibrium green s function simulations
Journal of Applied Physics, 2015Co-Authors: R Salazar, Rajib Rahman, Gerhard Klimeck, Hesameddin Ilatikhameneh, Joerg AppenzellerAbstract:A new compact modeling Approach is presented which describes the full current-voltage (I-V) characteristic of high-performance (aggressively scaled-down) tunneling field-effect-transistors (TFETs) based on homojunction direct-bandgap semiconductors. The model is based on an analytic description of two key features, which capture the main physical phenomena related to TFETs: (1) the potential profile from source to channel and (2) the elliptic curvature of the complex bands in the bandgap region. It is proposed to use 1D Poisson's equations in the source and the channel to describe the potential profile in homojunction TFETs. This allows to quantify the impact of source/drain doping on device performance, an aspect usually ignored in TFET modeling but highly relevant in ultra-scaled devices. The compact model is validated by comparison with state-of-the-art quantum transport simulations using a 3D full band Atomistic Approach based on non-equilibrium Green's functions. It is shown that the model reproduces with good accuracy the data obtained from the simulations in all regions of operation: the on/off states and the n/p branches of conduction. This Approach allows calculation of energy-dependent band-to-band tunneling currents in TFETs, a feature that allows gaining deep insights into the underlying device physics. The simplicity and accuracy of the Approach provide a powerful tool to explore in a quantitatively manner how a wide variety of parameters (material-, size-, and/or geometry-dependent) impact the TFET performance under any bias conditions. The proposed model presents thus a practical complement to computationally expensive simulations such as the 3D NEGF Approach.
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strain and electric field control of hyperfine interactions for donor spin qubits in silicon
Physical Review B, 2015Co-Authors: Muhammad Usman, Rajib Rahman, Gerhard Klimeck, S Rogge, M Y Simmons, Charles D Hill, Lloyd C L HollenbergAbstract:Control of hyperfine interactions is a fundamental requirement for quantum computing architecture schemes based on shallow donors in silicon. However, at present, there is lacking an Atomistic Approach including critical effects of central-cell corrections and nonstatic screening of the donor potential capable of describing the hyperfine interaction in the presence of both strain and electric fields in realistically sized devices. We establish and apply a theoretical framework, based on Atomistic tight-binding theory, to quantitatively determine the strain and electric-field-dependent hyperfine couplings of donors. Our method is scalable to millions of atoms, and yet captures the strain effects with an accuracy level of DFT method. Excellent agreement with the available experimental data sets allow reliable investigation of the design space of multiqubit architectures, based on both strain only as well as hybrid (strain + field) control of qubits. The benefits of strain are uncovered by demonstrating that a hybrid control of qubits based on (001) compressive strain and in-plane (100 or 010) fields results in higher gate fidelities and or faster gate operations, for all of the four donor species considered (P, As, Sb, and Bi). The comparison between different donor species in strained environments further highlights the trends of hyperfine shifts, providing predictions where no experimental data exists. While faster gate operations are realizable with in-plane fields for P, As, and Sb donors, only for the Bi donor, our calculations predict faster gate response in the presence of both in-plane and out-of-plane fields, truly benefiting from the proposed planar field control mechanism of the hyperfine interactions.
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a predictive analytic model for high performance tunneling field effect transistors Approaching non equilibrium green s function simulations
arXiv: Mesoscale and Nanoscale Physics, 2015Co-Authors: R Salazar, Rajib Rahman, Gerhard Klimeck, Hesameddin Ilatikhameneh, Joerg AppenzellerAbstract:A new compact modeling Approach is presented which describes the full current-voltage (I-V) characteristic of high-performance (aggressively scaled-down) tunneling field-effect-transistors (TFETs) based on homojunction direct-bandgap semiconductors. The model is based on an analytic description of two key features, which capture the main physical phenomena related to TFETs: 1) the potential profile from source to channel, and 2) the elliptic curvature of the complex bands in the bandgap region. It is proposed to use 1D Poisson's equations in the source and the channel to describe the potential profile in homojunction TFETs. This allows to quantify the impact of source/drain doping on device performance, an aspect usually ignored in TFET modeling but highly relevant in ultra-scaled devices. The compact model is validated by comparison with state-of-the-art quantum transport simulations using a 3D full band Atomistic Approach based on Non-Equilibrium Green's Functions (NEGF). It is shown that the model reproduces with good accuracy the data obtained from the simulations in all regions of operation: the on/off states and the n/p branches of conduction. This Approach allows calculation of energy-dependent band-toband tunneling currents in TFETs, a feature that allows gaining deep insights into the underlying device physics. The simplicity and accuracy of the Approach provides a powerful tool to explore in a quantitatively manner how a wide variety of parameters (material-, size- and/or geometrydependent) impact the TFET performance under any bias conditions. The proposed model presents thus a practical complement to computationally expensive simulations such as the 3D NEGF Approach.
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a predictive compact model for high performance tunneling field effect transistors Approaching the accuracy of negf simulations
arXiv: Mesoscale and Nanoscale Physics, 2015Co-Authors: R Salazar, Rajib Rahman, Gerhard Klimeck, Hesameddin Ilatikhameneh, Joerg AppenzellerAbstract:A new compact modeling Approach is presented which describes the full current-voltage (I-V) characteristic of high-performance (aggressively scaled-down) tunneling field-effect-transistors (TFETs) based on homojunction direct-bandgap semiconductors. The model is based on an analytic description of two key features, which capture the main physical phenomena related to TFETs: 1) the potential profile from source to channel, and 2) the elliptic curvature of the complex bands in the bandgap region. It is proposed to use 1D Poisson's equations in the source and the channel to describe the potential profile in homojunction TFETs. This allows to quantify the impact of source/drain doping on device performance, an aspect usually ignored in TFET modeling but highly relevant in ultra-scaled devices. The compact model is validated by comparison with state-of-the-art quantum transport simulations using a 3D full band Atomistic Approach based on Non-Equilibrium Green's Functions (NEGF). It is shown that the model reproduces with good accuracy the data obtained from the simulations in all regions of operation: the on/off states and the n/p branches of conduction. This Approach allows calculation of energy-dependent band-toband tunneling currents in TFETs, a feature that allows gaining deep insights into the underlying device physics. The simplicity and accuracy of the Approach provides a powerful tool to explore in a quantitatively manner how a wide variety of parameters (material-, size- and/or geometrydependent) impact the TFET performance under any bias conditions. The proposed model presents thus a practical complement to computationally expensive simulations such as the 3D NEGF Approach.
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Atomistic modeling of metallic nanowires in silicon
Nanoscale, 2013Co-Authors: Lloyd C L Hollenberg, Hoon Ryu, Sunhee Lee, Bent Weber, S Mahapatra, M Y Simmons, Gerhard KlimeckAbstract:Scanning tunneling microscope (STM) lithography has recently demonstrated the ultimate in device scaling with buried, conducting nanowires just a few atoms wide and the realization of single atom transistors, where a single P atom has been placed inside a transistor architecture with atomic precision accuracy. Despite the dimensions of the critical parts of these devices being defined by a small number of P atoms, the device electronic properties are influenced by the surrounding 104 to 106 Si atoms. Such effects are hard to capture with most modeling Approaches, and prior to this work no theory existed that could explore the realistic size of the complete device in which both dopant disorder and placement are important. This work presents a comprehensive study of the electronic and transport properties of ultra-thin (<10 nm wide) monolayer highly P δ-doped Si (Si:P) nanowires in a fully Atomistic self-consistent tight-binding Approach. This Atomistic Approach covering large device volumes allows for a systematic study of disorder on the physical properties of the nanowires. Excellent quantitative agreement is observed with recent resistance measurements of STM-patterned nanowires [Weber et al., Science, 2012, 335, 64], confirming the presence of metallic behavior at the scaling limit. At high doping densities the channel resistance is shown to be insensitive to the exact channel dopant placement highlighting their future use as metallic interconnects. This work presents the first theoretical study of Si:P nanowires that are realistically extended and disordered, providing a strong theoretical foundation for the design and understanding of atomic-scale electronics.