206 research outputs found
Effect of Growth Pressure on Epitaxial Graphene Grown on 4H-SiC Substrates by Using Ethene Chemical Vapor Deposition
No full textThe Si(0001) face and C(000-1) face dependences on growth pressure of epitaxial graphene (EG) grown on 4H-SiC substrates by ethene chemical vapor deposition (CVD) was studied using atomic force microscopy (AFM) and micro-Raman spectroscopy (μ-Raman). AFM revealed that EGs on Si-faced substrates had clear stepped morphologies due to surface step bunching. However, This EG formation did not occur on C-faced substrates. It was shown by μ-Raman that the properties of EG on both polar faces were different. EGs on Si-faced substrates were relatively thinner and more uniform than on C-faced substrates at low growth pressure. On the other hand, D band related defects always appeared in EGs on Si-faced substrates, but they did not appear in EG on C-faced substrate at an appropriate growth pressure. This was due to the μ-Raman covering the step edges when measurements were performed on Si-faced substrates. The results of this study are useful for optimized growth of EG on polar surfaces of SiC substrates
Feasibility of polyethylene film as both supporting material for transfer and target substrate for flexible strain sensor of CVD graphene grown on Cu foil
No full textFacile utilization of polyethylene (PE) film as both the supporting material for graphene transfer from copper foil and the target substrate for flexible strain sensor preparation in a single route.</p
AMS measurements of Be-10 and C-14 in loess profile at Donglingshan, Beijing
No full textA loess profile in Donglingshan site (40 degrees 02'N, 115 degrees 27'E) near Beijing was chosen to study the loess formation process and paleo-climate variation. Thirty eight samples were collected and analyzed for C-14, Be-10 as well as MS. TOC and delta C-13. Based on C-14 measurements, we established a time scale for this loess profile during Holocene. The averaged Be-10 deposition flux was found to be 4.87 x 10(6) atoms/cm(2) year. This is similar to the flux of 4.2 x 10(6) atoms/cm(2) year estimated for Chinese Loess Plateau in central China. High Be-10 concentrations of 3.85-5.66 x 10(8) atoms/g for the samples in layer 23-39 cm from 2965 to 528 years BP suggest a warm and humid weather during this period. MS values have similar variation with Be-10 and reflect the similar paleo-climate information. TOC and delta C-13 suggest that the vegetation around Donlingshan area was C-3 type plants during entire Holocene. (C) 2009 Elsevier B.V. All rights reserved.Instruments & InstrumentationNuclear Science & TechnologyPhysics, Atomic, Molecular & ChemicalPhysics, NuclearSCI(E)EICPCI-S(ISTP)
Dependence of the electrical and optical properties on growth interruption in AlAs/In(0.53)Ga(0.47)As/InAs resonant tunneling diodes
No full textAb initio theoretical and photoemission studies on formation of 4H-SiC(0001) SiO2 interface
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Growth of Hexagonal Columnar Nanograin Structured SiC Thin Films on Silicon Substrates with Graphene-Graphitic Carbon Nanoflakes Templates from Solid Carbon Sources
No full textWe report a new method for growing hexagonal columnar nanograin structured silicon carbide (SiC) thin films on silicon substrates by using graphene–graphitic carbon nanoflakes (GGNs) templates from solid carbon sources. The growth was carried out in a conventional low pressure chemical vapor deposition system (LPCVD). The GGNs are small plates with lateral sizes of around 100 nm and overlap each other, and are made up of nanosized multilayer graphene and graphitic carbon matrix (GCM). Long and straight SiC nanograins with hexagonal shapes, and with lateral sizes of around 200–400 nm are synthesized on the GGNs, which form compact SiC thin films
Growth of 4H-SiC epilayers with low surface roughness and morphological defects density on 4 degrees off-axis substrates
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