Acetylene adsorption on Si(100): A study of the role of surface steps

Mazzone, A.

doi:10.1016/j.susc.2006.09.029

Cited by 2 publications

(3 citation statements)

References 39 publications

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“…At the same time, the SiC surface and its reconstructions have attracted much attention both in experiment [11] and theory [12] due to its fundamental interest and technological importance in recent years. Progresses in several theoretical applications, such as ab initio [13,14] and empirical molecular dynamic [15,16], have provided more specific insight into absorbing processes on the atomic scale. The surface relaxation and reconstructing behaviors have been derived from these calculations.…”

Section: Introductionmentioning

confidence: 99%

Atomic-Level Investigation ofCHxandC2HxAdsorption onβ-SiC (111) Surface for CVD Diamond Growth from D

Sun

2011

Journal of Nanomaterials

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The focus of this paper is on the adsorption of unsaturated hydrocarbon molecules onβ-SiC (111) surfaces during diamond film growth. TheCHxandC2Hxmolecules have been investigated to obtain a specific insight into absorbing diamond processes on the atomic scale. Structural and electronic properties ofCHxandC2Hxadsorption on the Si- and C-terminated surfaces have been studied by first-principles calculations based on density functional theory (DFT). From the calculated energetics and geometries, we find thatC2Hxadsorption on the Si-terminated surfaces has six possible surface reconstructions. For the C-terminated surface, there exist eight possible surface reconstructions. Five surface reconstructions, includingCH2adsorption on the Si- and C-terminated surface, CH–CH2and CH=CH2adsorption on the C-terminated surface, andC2H5adsorption on the Si-terminated surface, have the largest hydrogen adsorption energies and more stability of surface reconstructions. Calculations demonstrate that the Si-terminated surface is energetically more favorable for fabricating CVD diamond coatings than the C-terminated surface.

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Section: Introductionmentioning

confidence: 99%

Atomic-Level Investigation ofCHxandC2HxAdsorption onβ-SiC (111) Surface for CVD Diamond Growth from D

Sun

2011

Journal of Nanomaterials

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“…Several groups have studied acetylene absorption onto silicon substrates through modeling , as well as experimentally. , In these studies, it was determined that below 600 °C, acetylene is chemisorbed at the surface. At 660 °C, hydrogen disassociates and leaves the surface in the form of H 2 .…”

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confidence: 99%

“…Consistent with prior work, carbonization decreased the contact angle slightly from 76 to 60°a fter treatment. 16 Several groups have studied acetylene absorption onto silicon substrates through modeling 20,21 as well as experimentally. 22,23 In these studies, it was determined that below 600 °C, acetylene is chemisorbed at the surface.…”

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confidence: 99%

Pore Size Control of Ultrathin Silicon Membranes by Rapid Thermal Carbonization

et al. 2010

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Rapid thermal carbonization in a dilute acetylene (C 2 H 2 ) atmosphere has been used to chemically modify and precisely tune the pore size of ultrathin porous nanocrystalline silicon (pnc-Si). The magnitude of size reduction was controlled by varying the process temperature and time. Under certain conditions, the carbon coating displayed atomic ordering indicative of graphene layer formation conformal to the pore walls. Initial experiments show that carbonized membranes follow theoretical predictions for hydraulic permeability and retain the precise separation capabilities of untreated membranes.Porous nanocrystalline silicon (pnc-Si) membranes are a promising material for a broad range of applications including filtration, cell culture substrates, and as a platform for electron microscopy and spectroscopy1 , 2. This material is over an order of magnitude thinner than the thinnest electrochemically etched porous silicon (PSi) membranes3. Because the thickness of the membrane is only 15 nm, on the order of species to be separated, mass transport through the membrane is greatly enhanced as compared to traditional tortuous path polymer membranes that are typically many microns in thickness4 , 5. Using these ultra-thin pnc-Si membranes, precise and low-loss separation of nanoparticles has been demonstrated in diffusion1 and convection6. These membranes use a bottom-up approach, rather than the expensive top-down approach used to manufacture other nanomembranes7 -9.Using standard microfabrication techniques, pnc-Si pore sizes can be tuned from being nonporous to having pores greater than 80 nm, however the resolution of control over pore size during manufacturing is limited to ± 5 nm. In order to optimize the quality of a separation procedure, finer control over pore sizes is desirable. Here we demonstrate that carbonization can be used as a post-production means to tune pore sizes with sub-nanometer precision thus allowing for further optimization of the sieving properties of the membrane. Under certain conditions, atomic ordering is observed along the pore walls suggesting graphene formation during carbonization. Given the high fluxes of water and gas through carbon nanotube (CNT) membranes, carbonization of pnc-Si may lead to novel silicon-* Corresponding author: fauchet@ece.rochester.edu.Supporting Information Available: Supplemental information on pore size distribution calculation, ozone treatment of membranes, chemical stability, theoretical calculation of hydraulic permeability, and data on gold nanoparticle and protein filtration is available free of charge via the internet at http://pubs.acs.org. Previous techniques to control the size of nanoporous membranes involve coating pores with polymers13 or metal14. While polymer coatings are relatively easy to deposit, they are unable to withstand high temperatures and harsh chemical environments. Metal coatings are more resilient, but processing can be complicated and take a long time to complete15. Pore modification via rapid thermal carbonization suffe...

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Acetylene adsorption on Si(100): A study of the role of surface steps

Cited by 2 publications

References 39 publications

Atomic-Level Investigation ofCHxandC2HxAdsorption onβ-SiC (111) Surface for CVD Diamond Growth from D

Atomic-Level Investigation ofCHxandC2HxAdsorption onβ-SiC (111) Surface for CVD Diamond Growth from D

Pore Size Control of Ultrathin Silicon Membranes by Rapid Thermal Carbonization

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