sam on silicon oxide surfaces
Oriented silicon nanowires on silicon substrates from oxide assisted growth and gold catalysts
Ngày tải lên :
16/03/2014, 15:06
... put on the holey carbon copper grids for transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) examination TEM image (Fig 2c) shows a dark particle capping the nanowire Silicon ... disproportionate at the particle surface into Si and SiO2 Silicon will dissolve in the Au particle, while the silicon oxide will remain at the particle surface When the Si concentration in the ... decomposition temperature Close TEM observation shows there is a thin silicon oxide layer covering the Au particle tips During growth, the arriving silicon atoms have to diffuse through the thin oxide...
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Effect of tunneling current on the growth of silicon islands on si(111) surfaces with a scanning tunneling microscope
Ngày tải lên :
16/03/2014, 15:32
... with a scanning reflection electron microscope (SREM ) The condition of the tungsten tip of the STM and the manipulation of the tip on the silicon surface could be monitored continuously with the ... the result of the mechanical contacts Note that atom transfer at mechanical tip–sample contacts has been considered to explain the mound and pit formation on silicon surfaces in UHV when voltage ... mechanisms of atom transfer contribute to the island growth: the continuous transfer of weakly bonded silicon atoms along the sample surface is gradually substituted by silicon atom transfer from the...
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Characterisation and modelling of wicking on ordered silicon nanostructured surfaces fabricated by interference lithography and metal assisted chemical etching
Ngày tải lên :
10/09/2015, 09:04
... the Scanning Electron Microscopy 56 Figure 3.6 Interaction between primary electrons and the sample surface generates backscattered electrons, secondary electrons, Auger electrons and X-rays ... for wicking flow on silicon nanopillars surface 74 ix List of Figures Figure 4.6 Contact angle of (a) water and (b) silicone oil estimated using a contact angle goniometer ... wicking process of silicone oil on silicon nanopillars surface (Sample B) The red dotted line marks the liquid front 81 Figure 4.8 Plot of distance travelled by the wetting front against the square...
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Adsorption of halogenated organic molecules and photo induced construction of a covalently bonded second organic layer on silicon surfaces
Ngày tải lên :
14/09/2015, 08:43
... bonding reaction to pyridine (containing a lone pair of electron and acting as an electron-donor in the surface reaction) on silicon surfaces, which demonstrated the coexistence of dative-bonded ... species on silicon 13 Chapter surfaces The adsorption of water on Si(100)-2×1 attracted much attention as the resulting silicon oxidant in the surface reaction is vital in microelectronic fabrication ... adsorption reaction between organic molecules and silicon surfaces Functionalization of Si surfaces with organic molecules depends on the detailed understanding of the reaction mechanisms of functional...
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The binding of multi functional organic molecules on silicon surfaces 4
Ngày tải lên :
16/09/2015, 17:13
... Multi-functional Organic Molecules on Silicon Surfaces 7×7 and Si(100)-2×1, the different binding configuration for acetylethyne bonding on two surfaces would be expected Formation of cumulative ... Multi-functional Organic Molecules on Silicon Surfaces This result is indeed consistent with the formation of a tetra-σ linkage through two [2+2]like cycloaddition reactions These constituent ... cycloaddition reactions of the C=O and C≡C groups with the silicon surfaces This conclusion is further supported by XPS studies On the other hand, considering the feasible [2+2]-like cyloaddition between...
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The binding of multi functional organic molecules on silicon surfaces 3
Ngày tải lên :
16/09/2015, 17:13
... electron density on these 58 The Binding of Multi-functional Organic Molecules on Silicon Surfaces carbon atoms upon chemisorption The chemisorption process is expected to destroy the ring π-bond ... Multi-functional Organic Molecules on Silicon Surfaces 1.4eV in the core level for one of the nitrogen atoms confirms its participation in the cycloaddition with reactive sites on Si(111)-7×7, consistent ... Multi-functional Organic Molecules on Silicon Surfaces 3.2 Pyrazine adsorption 3.2.1 High-resolution electron energy loss spectroscopy Figure 3.1 shows the high-resolution electron energy loss...
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The binding of multi functional organic molecules on silicon surfaces 2
Ngày tải lên :
16/09/2015, 17:13
... Multi-functional Organic Molecules on Silicon Surfaces additional (non-dipole) excitation mechanisms The major tradeoff is the inherently poorer resolution of electron spectroscopy and the limitation ... Molecules on Silicon Surfaces Ekin Ekin Evac hν Φ EF Φ EB Spectrometer Sample Figure 2.3 Energy level diagram for X-ray photoemission 45 The Binding of Multi-functional Organic Molecules on Silicon Surfaces ... functional (pBP86) in conjugation with a basis set of DN** (comparable 6-31 38 The Binding of Multi-functional Organic Molecules on Silicon Surfaces G**) [15] Geometric optimizations were conducted...
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The binding of multi functional organic molecules on silicon surfaces 1
Ngày tải lên :
16/09/2015, 17:14
... unsaturated hydrocarbons have been extensively investigated In genernal, the 15 The Binding of Multi-functional Organic Molecules on Silicon Surfaces functionalization of silicon surfaces consists of two ... 1.3 Reaction mechanisms of functional molecules with silicon surfaces Previous work in this field has been mainly focused on the binding of unsaturated organic molecules on silicon surfaces [2-6] ... Multi-functional Organic Molecules on Silicon Surfaces 1.2 The Si(111)-7×7 and Si(100)-2×1 surfaces Silicon crystals have the diamond-like structure, i.e the atoms are sp3 hybridized and bonded to...
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The binding of multi functional organic molecules on silicon surfaces 6
Ngày tải lên :
16/09/2015, 17:14
... further chemical modification and functionalization of silicon surfaces 148 The Binding of Multi-functional Organic Molecules on Silicon Surfaces 2791 3075 Physisorption (a) 2884 449 521 693 789 ... Multi-functional Organic Molecules on Silicon Surfaces electrons to form a dative-bonded precursor with electron-deficient Si dangling bonds, thereby lowering the energy barrier of the surface reaction ... Multi-functional Organic Molecules on Silicon Surfaces derivatives [13-14] Thus, for benzaldehyde and acetophenone containing a conjugated carbonyl and phenyl ring, rich attachment chemistry on Si(100)can...
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The binding of multi functional organic molecules on silicon surfaces 5
Ngày tải lên :
16/09/2015, 17:14
... Multi-functional Organic Molecules on Silicon Surfaces with the functional groups in the molecule, offering the necessary flexibility in the functionalization and modification of silicon surfaces ... molecules strongly demonstrates 124 The Binding of Multi-functional Organic Molecules on Silicon Surfaces the rehybridization of one of the C≡C groups in the surface binding This conclusion is further ... possible configurations to aid the understanding of the reactivity and selectivity of these π-conjugated systems on Si(111)-7 ×7 125 The Binding of Multi-functional Organic Molecules on Silicon Surfaces...
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Growth and characterization of oxide thin films on silicon by pulsed laser deposition
Ngày tải lên :
07/10/2015, 10:10
... motivations of this project are to: Fabricate proper buffer layers on silicon for growth of high quality magnetic oxide film on silicon; study the growth mechanism of these buffer layers on silicon ... nature of bonding yields semiconductors with high carrier mobilities Electronic oxides containing transition metal cations can yield high conductivity metals, such as SrRuO3, or even superconductors, ... influence on the distribution of the cations on A and B sites, including the radii of the metal ions, electrostatic energies of the lattice, and the matching of the electronic configuration of the...
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Effects of ambient pressure on silicon nanowire growth
Ngày tải lên :
16/03/2014, 15:05
... examinations with transmission electron microscopy (TEM) con®rmed that the loose material was SiNWs Results and discussion It was found that the ambient pressure had an important eect on the yield ... keeps on transporting SiO vapor to the deposition location, the ambient pressure would thus have a lesser eect on the partial pressure of the SiO vapor at both the evaporation and the deposition ... lower evaporation rate of SiO at the source and the lower diusion coecient in the transportation of vapor from source to deposition site The parameters Pe and Vm are decided only by the temperature...
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Si nanowires grown from silicon oxide
Ngày tải lên :
16/03/2014, 15:08
... in nanowire growth We investigated the native silicon oxide on single Si crystal surfaces The oxide thickness was only 2–3 monolayers However, the oxide shells of nanowires were quite thick We ... investigations confirmed the amorphous structure of the SiO deposited on the Cu finger surface By heating the SiO sample in TEM, silicon precipitation was observed Žsee Fig 2a Such precipitation of ... decompositions of silicon oxide at the relatively low temperature of 9308C as shown below Si xO ™ Si xy1 q SiO Ž x ) and 2SiO ™ Si q SiO These decompositions result in the precipitation of silicon nanoparticles,...
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A new mechanism for modulation of schottky barrier heights on silicon nanowires
Ngày tải lên :
16/03/2014, 15:14
... distribution along the wire could be chosen to separate electron and hole injection The sample configuration, contact geometry and charge distribution are demonstrated in Fig The preparation started ... doping concentration in the semiconductor bulk Using Eq (1) in Poisson’s equation, and the materials parameters from Ref [10] as mentioned in Fig 2, the shape of the conduction band is demonstrated ... be about 0.2 eV For our experiments, samples with Pd2Si/Si Schottky contacts on the end surfaces of silicon wires were prepared on SOI material by electron beam lithography By using the substrate...
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Formation of silicon oxide nanowires directly from au si and pd–au si substrates
Ngày tải lên :
16/03/2014, 15:16
... both sample surfaces, although the diameters of SiOx nanowires (below 400 nm) on the Au/Si substrate were larger than those of SiOx nanowires (below 200 nm) on the Pd–Au/Si substrate In addition, ... we could conclude that the formation mechanism of our SiOx nanowires is explained by the SLS process Conclusion In summary, we have reported amorphous SiOx nanowires directly grown on Si substrates ... 10–80 nm were formed on the surface of the substrate by heating the Au/Si substrate at 1000 1C On the other hand, the formation of Pd–Au nanoislands with a uniform size distribution (a diameter of...
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Tiny silicon nano wires synthesis on silicon wafers
Ngày tải lên :
16/03/2014, 15:22
... discussion Top view SEM image of the SiNWs grew on the silicon substrate is shown in Fig A large quantity of long and thick SiNWs (trunk SiNWs) were observed on the surface of the silicon wafer ... tiny wires were mainly composed of silicon core and a small quantity of silicon oxide sheath Detailed analysis Fig Top view SEM image of the SiNWs grew on the silicon substrate (the part of Au nanoparticles ... the peak should contribute to the thin SiOx sheath out of the silicon nano-wire and the defects which are contained among the silicon nano-wire This work was supported by the National Natural Science...
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One dimensional organic nanostructures a novel approach based on the selective adsorption of organic molecules on silicon nanowires
Ngày tải lên :
16/03/2014, 15:35
... of PQ adsorbed on Si(0 1) In summary, we presented here a novel approach to form 1D organic structures based on the adsorption of organic molecules on silicon nanowires We demonstrated that carefully ... compounds, such as dicarbonyl derivatives, selectively react with the silicon nanowires and form 1D organic nanowires along the same direction We propose that the adsorption process occurs between ... closely spaced SiNWs Measurements performed one day after the evaporation of THAP on the surface exhibit the same random adsorption of the THAP molecules on the surface This suggests that even after...
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h2s sensors based on tungsten oxide nanostructures
Ngày tải lên :
19/03/2014, 16:48
... reasonably good response value even at 50–100 ◦ C The concentration-variation of response of the tungsten oxide nanostructures at 250 ◦ C is shown in Fig 7b In the 50–100 ppm range, the response ... the surface of tungsten oxide As H2 S is adsorbed, electrons are released into the conduction band according to Eq (3) Conclusions Fig Temperature variation of (a) response and (b) recovery times ... characteristics of tungsten oxide nanoplatelets to 1000 ppm H2 S, and (b) variations in response with concentration of H2 S at 250 ◦ C of 48 is found at 250 ◦ C The response and recovery times of...
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studies on tin oxide-intercalated polyaniline nanocomposite for ammonia gas
Ngày tải lên :
20/03/2014, 13:08
... the concentration of gas (in ppm) In Fig 9, we show sensitivity (S%) of pure tin oxide, pure PANI, and the tin oxide/ PANI nanacomposite film, on exposure to ammonia for different concentrations ... formation of initial seeding on the fresh substrate In the reaction bath without a substrate into it, aniline monomers are in random thermo-dynamic state, and depending upon thermo-chemical conditions ... aggregation These mechanisms depend on the dispersion of colloidal particles at lowsolid volume fractions (ϕ0 → 0) having with (a) diffusion-limited cluster aggregation (DLCA), and (b) reaction-limited...
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selective contact anneal effects on indium oxide nanowire transistors using femtosecond laser
Ngày tải lên :
06/05/2014, 08:54
... the conclusion that optimizing the contact region in NWTs through laser annealing can raise the possibilities of NWTs to be used as the device components beyond the conventional CMOS applications ... the contacts, consequently lowering the ΦB along with increased electronic transparency of the contact region.37 The high peak intensity of the femtosecond laser can induce nonlinear absorption ... modification such as ozone treatment and surface passivation.38 ’ CONCLUSIONS In conclusion, single In2O3 nanowire transistors in which the S-D regions are selectively annealed utilizing femtosecond...
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