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The catalytic performance of supported metals is greatly influenced by the interaction with the support material. The role of the support becomes even more important when dealing with metal nanoparticles and high reaction temperatures. Herein, we show that interfacial sites between two metal oxides, MgAlOx and ZrO2 can bestow high stability as well as enhanced reactivity to nickel (Ni) nanoparticles. We use the MgAlOx as thin oxides on an underlying bulk ZrO2. We demonstrate the effect of the metal‐support interactions (MSI) in different support locations on the performance in dry reforming of methane (DRM). We find that the rate of DRM catalysis produces a concave‐down trend with respect to Ni loading with a maximum at ~0.8–1.1 % wt Ni. Measuring the Ni2p3/2 binding energy (BE), we find a similar concave‐down trend whereas for the Mg2p BE we find a concave‐up trend with respect to the Ni loading both with the maximum and minimum centered at 0.8–1.1 % wt Ni, respectively. These trends were correlated with the stability of Ni calculated by DFT. Overall, our results suggest that heterointerfacial sites can be used to tailor moderate MSI, which can be used in the design of DRM catalyst with significantly increased activity and high stability. [ABSTRACT FROM AUTHOR]

The catalytic performance of supported metals is greatly influenced by the interaction with the support material. The role of the support becomes even more important when dealing with metal nanoparticles and high reaction temperatures. Herein, we show that interfacial sites between two metal oxides, MgAlOx and ZrO2 can bestow high stability as well as enhanced reactivity to nickel (Ni) nanoparticles. We use the MgAlOx as thin oxides on an underlying bulk ZrO2. We demonstrate the effect of the metal‐support interactions (MSI) in different support locations on the performance in dry reforming of methane (DRM). We find that the rate of DRM catalysis produces a concave‐down trend with respect to Ni loading with a maximum at ~0.8–1.1 % wt Ni. Measuring the Ni2p3/2 binding energy (BE), we find a similar concave‐down trend whereas for the Mg2p BE we find a concave‐up trend with respect to the Ni loading both with the maximum and minimum centered at 0.8–1.1 % wt Ni, respectively. These trends were correlated with the stability of Ni calculated by DFT. Overall, our results suggest that heterointerfacial sites can be used to tailor moderate MSI, which can be used in the design of DRM catalyst with significantly increased activity and high stability. [ABSTRACT FROM AUTHOR]

The Cover Feature depicts the possible Ni locations on the MgAlOx/ZrO2 support and highlights the superior DRM reaction performance of Ni at the heterointerfacial sites. The catalytic behaviors across these diverse Ni positions are metaphorically represented by the thrust of the rockets and the brightness of the Ni particles. In their Research Article, M. M. Montemore, O. M. Gazit and co‐worker demonstrate that the heterointerface between a thin MgAlOx overlayer and the underlying bulk ZrO2 is the preferred site for Ni particles. The combined results from XPS, DFT, H2‐TPR, TEM, and catalytic studies indicate that the tri‐phase boundary among Ni, MgAlOx, and ZrO2 offers unique metal‐support interactions and enhanced performance in methane dry reforming. More information can be found in the Research Article by M. M. Montemore, O. M. Gazit and co‐workers. [ABSTRACT FROM AUTHOR]

High-mobility alternative channel materials to silicon are critical to the continued scaling of MOS devices. The analysis of capacitance–voltage (C–V) measurements on these new materials with high-k gate dielectrics is a critical technique to determine many important gate-stack parameters. While there are very useful C–V analysis tools available to the community, these tools are all limited in their applicability to alternative semiconductor channel MOS gate-stack analysis since they were developed for silicon. Here, we report on a new comprehensive C–V simulation and extraction tool, called CV Alternative Channel Extraction (ACE), that incorporates a wide range of semiconductors and dielectrics with the capability to implement customized gate stacks. Fermi–Dirac carrier statistics, nonparabolic bands, and quantum mechanical effects are all implemented with options to turn each of these off as the user desires. Interface state capacitance ( C\mathsf {it} ) is implemented using a common model for systems like Si and Ge. A more complex C\mathsf {it} model is also implemented for III–Vs that accurately captures frequency dispersion in accumulation that arises from tunneling. CV ACE enables extremely fast simulation and extraction and can accommodate measurements performed at variable temperatures and frequencies to allow for a more accurate extraction of interface state density ( D\mathsf {it} ). [ABSTRACT FROM PUBLISHER]

Capacitance-voltage ( C – V ) measurement and analysis is highly useful for determining important information about MOS gate stacks. Parameters such as the equivalent oxide thickness (EOT), substrate doping density, flatband voltage, fixed oxide charge, density of interface traps ( D \rm {it} ), and effective gate work function can all be extracted from experimental C – $V$ curves. However, to extract these gate-stack parameters accurately, the correct models must be utilized. In Part I, we described the modeling and implementation of a C$ – V$ code that can be used for alternative channel semiconductors in conjunction with high- k$ gate dielectrics and metal gates. Importantly, this new code (CV ACE) includes the effects of nonparabolic bands and quantum capacitance, enabling accurate models to be applied to experimental C$ – profiles from experimental high- $k$ on Ge and In0.53Ga0.47As gate stacks. [ABSTRACT FROM PUBLISHER]

Abstract: The influence of MeV electrons irradiation on the gate oxide layers of hydrogenated polysilicon thin film transistors (TFTs) was investigated by measuring gate leakage currents and threshold voltages. The experimental data revealed a decrease of oxide trap density and increase of positive oxide charge. Improvement in the interface roughness and in the oxide quality near the bottom interface was observed. [Copyright &y& Elsevier]

We present a model for simulating the capacitance–voltage (C–V) characteristics of polysilicon-gated MOS devices with thin oxides. The model includes substrate quantization effects through a modification of the total semiconductor charge. Therefore, solutions for C–V can be quickly obtained without the computational burden of solving over a physical grid. The model includes polysilicon depletion by self-consistently solving the charge balance equation. We conclude with comparisons of the C–V characteristics obtained with this model and those obtained by self-consistent solutions to the Schro¨dinger and Poisson equations. Good agreement was observed over a wide range of oxide thickness (2.0–15.0 nm) and substrate doping (1015–1018 cm−3). [Copyright &y& Elsevier]

Stress-induced leakage current (SILC) modeling requires consistency with a variety of experimental observations, like steady-state leakage, transient discharge currents and impact ionization characteristics observed after stress. Here we present a SILC model based on trap-assisted tunneling and recombination at deep-levels in the oxide, which successfully reproduces all SILC features. Based on a detailed analysis of SILC data, a two-band defect distribution is determined, in which the low- and high-energy ranges account for stationary SILC and transient currents, respectively. The stress-induced impact ionization (SIII) components associated with these defect distributions are then calculated, showing that the main contribution results from high-energy states. Simulation results are in good agreement with experimental data for leakage and SIII currents in p-channel devices with an oxide thickness of 8.2 nm. These results point out the limitation of the quantum yield method for measuring the mean energy loss in the SILC mechanism. [Copyright &y& Elsevier]

The wearout and breakdown parameters of representative gate and tunnel oxides are evaluated versus temperature, electric field and polarity. A frontier close to 127°C between two regions with different activation energies is clearly demonstrated. However, the negative charge build-up under high field stress is correlated with the breakdown. The field acceleration factor is found to be constant in the range 8.5-12.5 MV/cm. The time-to-breakdown distributions can be described both by the E and the l/E models. Finally, the thickness dependence of the field acceleration factor is quantified for oxide layers with a thickness in the range between 10 nm and 50 nm. [ABSTRACT FROM AUTHOR]