Revitalizing spherical Au@Pd nanoparticles with controlled surface-defect density as high performance electrocatalysts

ABSTRACTThe growth of a-Si:H and the resulting weak bond and defect formation mechanism is analysed in terms of the adsorbed Sill3 model of growth. It is found that this model describes the surface processes well, but it needs further development to correctly describe the temperature dependence of the formation of defects and weak bonds, since the surface defect density decreases monotonically with temperature and does not show a minimum near 250C. We show that the experimentally observed increase in hydrogen content, weak bond and defect density at lower deposition temperatures can be accounted for by a hydrogen evolution reaction from H2* sites.

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LaTiO2N nanopowders (NPs) with low surface defect density via nitridation of flame made NPs retaining simple perovskite structure

Dalton Transactions ◽

10.1039/d1dt03687d ◽

2022 ◽

Author(s):

Yoshiyuki Abe ◽

Richard M. Laine

Keyword(s):

Optical Absorption ◽

Absorption Edge ◽

Perovskite Structure ◽

Surface Defect ◽

Defect Density ◽

Optical Absorption Edge ◽

Surface Defect Density

LaTiO2N NP synthesized from flame made LaTiO3 NP exhibits less absorption background above the optical absorption edge than that synthesized from flame made La2Ti2O7 NP, suggesting a low surface defect density.

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Influence of substrate surface energy and surfactant on crystalline morphology and surface defect density in hydrothermally-grown ZnO nanowires

Materials Science in Semiconductor Processing ◽

10.1016/j.mssp.2018.01.014 ◽

2018 ◽

Vol 77 ◽

pp. 64-73 ◽

Cited By ~ 2

Author(s):

Ji-Sub Park ◽

Imtiaz Mahmud ◽

Young-Chul Shin ◽

Jun-Chan Choi ◽

Byeonggon Kim ◽

...

Keyword(s):

Surface Energy ◽

Surface Defect ◽

Defect Density ◽

Substrate Surface ◽

Zno Nanowires ◽

Crystalline Morphology ◽

Influence Of Substrate ◽

Surface Defect Density

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Reduction of Surface and PL Defects on n-Type 4H-SiC Epitaxial Films Grown Using a High Speed Wafer Rotation Vertical CVD Tool

Materials Science Forum ◽

10.4028/www.scientific.net/msf.924.108 ◽

2018 ◽

Vol 924 ◽

pp. 108-111 ◽

Cited By ~ 4

Author(s):

Yoshiaki Daigo ◽

Akio Ishiguro ◽

Shigeaki Ishii ◽

Hideki Ito

Keyword(s):

Buffer Layer ◽

High Speed ◽

Surface Defect ◽

Initial Temperature ◽

Rotation Speed ◽

Defect Density ◽

Epitaxial Films ◽

Wafer Surface ◽

Defect Densities ◽

Drift Layer

4H-SiC homo-epitaxial films were grown using a high speed wafer rotation vertical CVD tool, and effects of wafer rotation speed during initial temperature ramping before epitaxial growth were investigated. Also, the effects of conditions during growth of the highly doped buffer layer on both surface and PL defect densities were investigated. It was found that the wafer rotation speed during the temperature ramping has a large influence on the surface defect density of the films. Especially, triangles generated from small pits were considerably reduced in the samples grown at a higher wafer rotation speed during the temperature ramping. The phenomena could be explained as a result of suppressed interfacial reaction between down-falls (DFs) and the wafer surface. Additionally, it was found that the density of basal plane dislocations (BPDs) on a drift layer is remarkably reduced by adjusting the C/Si ratio during growth of the buffer layer grown prior to the drift layer. By applying higher wafer rotation speed during the temperature ramping and optimizing the C/Si ratio for the growth of the buffer layer, a total defect density of 0.75 cm-2 on the film, which includes DFs, triangles, DF-triangles, stacking faults (SFs) and BPDs, was achieved.

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Reduction in Background Carrier Concentration for 4H-SiC C-face Epitaxial Growth

MRS Advances ◽

10.1557/adv.2016.326 ◽

2016 ◽

Vol 1 (54) ◽

pp. 3631-3636 ◽

Cited By ~ 1

Author(s):

Johji Nishio ◽

Hirokuni Asamizu ◽

Mitsuhiro Kushibe ◽

Hidenori Kitai ◽

Kazutoshi Kojima

Keyword(s):

Epitaxial Growth ◽

Carrier Concentration ◽

Surface Defect ◽

Carrier Lifetime ◽

Epitaxial Film ◽

Defect Density ◽

Growth Parameters ◽

Thickness Variation ◽

Power Devices ◽

Surface Defect Density

ABSTRACT Reduction in background carrier concentration has been investigated for 4H-SiC C-face epitaxial growth in order to be applied for ultra-high voltage power devices. Optimizing epitaxial growth parameters made it possible to achieve 7.6x1013 cm-3 as the background carrier concentration within a whole area of specular 3-inch wafers. In addition to the background carrier concentration reduction, epitaxial film thickness variation, surface defect density and the carrier lifetime have been confirmed to fulfill the requirements for the devices.

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Reducing Surface Defects of CrXOY Film in Mid-Frequency Dual-Magnetron Sputtering

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.291-294.219 ◽

2011 ◽

Vol 291-294 ◽

pp. 219-222

Author(s):

Xiang Yu ◽

Lei Ma ◽

Yang Liu ◽

Zhong Zhou Yang ◽

Hua Meng

Keyword(s):

Magnetron Sputtering ◽

Process Parameters ◽

Surface Defect ◽

Surface Defects ◽

Defect Density ◽

Optimal Parameter ◽

Parameter Combination ◽

Surface Defect Density

Influence of the process parameters of a reactive mid-frequency dual-magnetron sputtering on surface defects of CrxOy film was investigated. The forming mechanisms of the observed droplets and craters were analyzed. The optimal parameter combination for accomplishing fewer surface defects was explored; and the optimized process parameters evidently minimized the surface defects of the film. In the condition of the target current of 16 A, the gases pressure of 0.31 Pa, and the bias voltages in a range of -120~-240 V, an optimized CrxOy film has been synthesized with surface defect density low to 78 defect/mm-2.

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Influence of surface defect density on the ultrafast hot carrier relaxation and transport in $${\hbox {Cu}}_2 {\hbox {O}}$$ photoelectrodes

Scientific Reports ◽

10.1038/s41598-020-67589-z ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Lisa Grad ◽

Zbynek Novotny ◽

Matthias Hengsberger ◽

Jürg Osterwalder

Keyword(s):

Surface Defect ◽

Defect Density ◽

Carrier Relaxation ◽

Hot Carrier ◽

Surface Defect Density

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Reliability of Large-Area Gate Oxide on the C-Face of 4H-SiC

Materials Science Forum ◽

10.4028/www.scientific.net/msf.615-617.553 ◽

2009 ◽

Vol 615-617 ◽

pp. 553-556

Author(s):

Tetsuo Hatakeyama ◽

Hiroshi Kono ◽

Takuma Suzuki ◽

Junji Senzaki ◽

Kenji Fukuda ◽

...

Keyword(s):

Surface Defect ◽

Defect Density ◽

Gate Oxide ◽

Hydrogen Atmosphere ◽

Scaling Analysis ◽

Strongly Correlated ◽

Large Area ◽

Initial Failure ◽

Random Failures ◽

Surface Defect Density

This paper discusses the issues regarding reliability of large-area (up to 9mm2) gate oxide on the C-face of 4H-SiC. We first show that the initial failure in TDDB characteristics of large area gate oxide is strongly correlated with the surface-defect density. Using wafers with low surface-defect density wafers, scaling analysis of the area-dependence of TDDB characteristics has been performed. It has shown that the reliability of a large area gate oxide is dominated by initial and random failures. Further, we have shown that, by optimizing the temperatures of post-oxidation anneal in hydrogen atmosphere, the random failures of TDDB characteristics are substantially reduced.

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