Single MoTe2 sheet electrocatalytic microdevice for in situ revealing the activated basal plane sites by vacancies engineering

The recently developed technique of UVPL imaging has been used to track the path of basal plane dislocations (BPDs) in SiC epitaxial layers. The glide of BPDs during epitaxial growth has been observed and the role of this glide in forming half-loop arrays has been examined. The ability to track the path of BPDs through the epitaxy has made it possible to develop a BPD reduction process for epitaxy grown on 8° offcut wafers, which uses an in situ growth interrupt and has achieved a BPD reduction of > 98%. The images also provide insight into the strong BPD reduction that typically occurs in epitaxy grown on 4° offcut wafers.

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Growth of Niobium Films at High Temperatures on Sapphire

MRS Proceedings ◽

10.1557/proc-440-151 ◽

1996 ◽

Vol 440 ◽

Author(s):

T. Wagner

Keyword(s):

High Temperatures ◽

Basal Plane ◽

Misfit Strain ◽

High Energy ◽

Total Density ◽

Initial Growth ◽

Island Size ◽

Transmission Electron ◽

Orientation Density

AbstractThe growth and microstructural evolution of Nb thin films on the basal plane of α-Al2O3 were studied at different growth temperatures. The influence of island orientation, density, and misfit strain energy on the growth behavior of Nb films on (0001)α-Al2O3 at high temperatures has been investigated. The films were grown by MBE at 900°C and 1100°C. At these temperatures the Nb grows in the Volmer-Weber growth mode on the basal plane. In-situ reflection high energy electron diffraction (RHEED), Auger electron spectroscopy (AES) and transmission electron microscopy (TEM) investigations revealed that in the initial growth stage, Nb nuclei with different epitaxial orientations were formed. This leads to different orientations of thicker Nb films at different growth temperatures. At a growth temperature of 900°C the Nb{111} planes are parallel to the sapphire basal plane whereas at 1100°C Nb grows with the {110) planes parallel to the basal plane of sapphire. The formation of two different epitaxial orientations of thick Nb films can only be explained by considering both the change in the total density of Nb islands with temperature and the influence of island size on their total energy.

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In situ structural modification of graphitic carbon nitride by alkali halides and influence on photocatalytic activity

RSC Advances ◽

10.1039/c7ra05555b ◽

2017 ◽

Vol 7 (52) ◽

pp. 32592-32600 ◽

Cited By ~ 23

Author(s):

Yan Xu ◽

Yinyan Gong ◽

Hui Ren ◽

Wenbo Liu ◽

Lengyuan Niu ◽

...

Keyword(s):

Photocatalytic Activity ◽

Charge Carrier ◽

Basal Plane ◽

Carbon Nitride ◽

Structural Modification ◽

Photocatalytic Performance ◽

Alkali Halides ◽

Thermal Condensation ◽

Carrier Transfer

Introducing alkali halides during thermal condensation of melamine disturbs periodic ordering in the basal plane, reduces the band gap, and facilitates charge carrier transfer and separation, and thus enhances the photocatalytic performance of g-C3N4.

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Basal Plane Dislocation Mitigation in 8º Off-Cut 4H-SiC through In Situ Growth Interrupts during Chemical Vapor Deposition

Materials Science Forum ◽

10.4028/www.scientific.net/msf.615-617.61 ◽

2009 ◽

Vol 615-617 ◽

pp. 61-66 ◽

Cited By ~ 2

Author(s):

Brenda L. VanMil ◽

Robert E. Stahlbush ◽

Rachael L. Myers-Ward ◽

Yoosuf N. Picard ◽

S.A. Kitt ◽

...

Keyword(s):

Conversion Efficiency ◽

Basal Plane ◽

Chemical Vapor ◽

Optimal Growth ◽

Nucleation Site ◽

Buffer Layers ◽

Active Device ◽

Basal Plane Dislocation ◽

Conversion Efficiencies

Conversion of basal plane dislocations (BPD) to threading edge dislocations (TED) in 8° off-cut 4H-SiC within an n+ buffer layer would eliminate the nucleation site for Shockley-type stacking faults in active device regions grown on such buffer layers. To that end, the propagation and conversion of BPDs through in situ growth interrupts is monitored using ultraviolet photoluminescence (UVPL) wafer mapping. The optimized growth interrupt scheme lasts for 45 minutes with a propane mass flow of 10 sccm at growth temperature. This scheme has shown a conversion efficiency of up to 99% for samples with electron (hole) concentrations < 5x1014 cm-3 (8x1015 cm-3). Samples subjected to a 45 or 90 minute interrupt under 10 sccm of propane, regardless of conversion efficiency, exhibit a “slit” in the surface morphology associated with each BPD and oriented perpendicular to the off-cut and BPD propagation direction. Repetition of the optimal interrupt sequence with a 5 μm epilayer spacer grown between the two interrupts resulted in the same conversion efficiency as a single optimal growth interrupt. Incorporation of the optimal interrupt into an n+ layer is more complicated as attempts to do so in layers doped with nitrogen to 2x1018, 2x1017 and 2x1016 cm-3 resulted in conversion efficiencies of ~6%.

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In situ atomic force microscopy measurements of biotite basal plane reactivity in the presence of oxalic acid

Geochimica et Cosmochimica Acta ◽

10.1016/j.gca.2011.09.010 ◽

2011 ◽

Vol 75 (22) ◽

pp. 6870-6881 ◽

Cited By ~ 20

Author(s):

Simon J. Haward ◽

Mark M. Smits ◽

Kristín Vala Ragnarsdóttir ◽

Jonathan R. Leake ◽

Steven A. Banwart ◽

...

Keyword(s):

Atomic Force Microscopy ◽

Oxalic Acid ◽

Basal Plane ◽

Force Microscopy ◽

Atomic Force

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Anisotropic Plastic Behavior in an Extruded Long-Period Ordered Structure Mg90Y6.5Ni3.5 (at.%) Alloy

Crystals ◽

10.3390/cryst10040279 ◽

2020 ◽

Vol 10 (4) ◽

pp. 279

Author(s):

Gerardo Garces ◽

Rafael Barea ◽

Andreas Stark ◽

Norbert Schell

Keyword(s):

Basal Plane ◽

Extrusion Direction ◽

Plastic Behavior ◽

Ordered Structure ◽

Lpso Phase ◽

Long Period ◽

Anisotropic Plastic ◽

The Difference ◽

Internal Strains

The Mg90Y6.5Ni3.5 alloy composed almost completely of the Long-Period-Stacking-Ordered (LPSO) phase has been prepared by casting and extrusion at high temperature. An elongated microstructure is obtained where the LPSO phase with 18R crystal structure is oriented with its basal plane parallel to the extrusion direction. Islands of α-magnesium are located between the LPSO grains. The mechanical properties of the alloy are highly anisotropic and depend on the stress sign as well as the relative orientation between the stress and the extrusion axes. The alloy is stronger when it is compressed along the extrusion direction. Under this configuration, the slip of <a> dislocations in the basal plane is highly limited. However, the activation of kinking induces an increase in the plastic deformation. In the transversal extrusion direction, some grains deform by the activation of basal slip. The difference in the yield stress between the different stress configurations decreases with the increase in the test temperature. The evolution of internal strains obtained during in-situ compressive experiments reveals that tensile twinning is not activated in the LPSO phase.

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Layer dependence of the photoelectrochemical performance of a WSe2 photocathode characterized using in situ microscale measurements

RSC Advances ◽

10.1039/c9ra06297a ◽

2019 ◽

Vol 9 (53) ◽

pp. 30925-30931

Author(s):

Yu Zhang ◽

Jingwei Xiao ◽

Xi Xie ◽

Huanjun Chen ◽

Shaozhi Deng

Keyword(s):

Catalytic Activity ◽

Basal Plane ◽

Photoelectrochemical Performance ◽

Number Of Layers

The performance of WSe2 PEC cathode increased with decreasing number of layers. Monolayer WSe2 exhibited best PEC characteristics and IPCE efficiency. The basal-plane of WSe2 sheet had the same PEC catalytic activity with the edge sites.

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