Enhancement of Si–O hybridization in low-temperature grown ultraviolet photo-oxidized SiO2 film observed by x-ray absorption and photoemission spectroscopy

Tsai, Hsiu-Min; Ray, S. C.; Pao, C. W.; Chiou, J. W.; Huang, Chih-Hsin; Du, Chao; Pong, W. F.; Tsai, Ming-Jinn; Fukano, Atsuyuki; Ōyanagi, H.

doi:10.1063/1.2828144

Cited by 14 publications

(3 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…p* transition, and therefore, the lack of this feature demonstrates that no significant p-bonded oxygen, which would be expected for a double-bonded state, is present. These spectra have identical characteristics with those of amorphous SiO 2 found in the literature [17][18][19] and show no indication of crystalline Si-O bonding or oxides that deviate from the stoichiometry of SiO 2 [20]. NEXAFS spectra were also obtained at the carbon and fluorine edges (data not shown).…”

Section: µMmentioning

confidence: 69%

Characterization of Microscale Wear in a Polysilicon-Based MEMS Device Using AFM and PEEM–NEXAFS Spectromicroscopy

et al. 2009

View full text Add to dashboard Cite

Mechanisms of microscale wear in siliconbased microelectromechanical systems (MEMS) are elucidated by studying a polysilicon nanotractor, a device specifically designed to conduct friction and wear tests under controlled conditions. Photoelectron emission microscopy (PEEM) was combined with near-edge X-ray absorption fine structure (NEXAFS) spectroscopy and atomic force microscopy (AFM) to quantitatively probe chemical changes and structural modification, respectively, in the wear track of the nanotractor. The ability of PEEM-NEXAFS to spatially map chemical variations in the nearsurface region of samples at high lateral spatial resolution is unparalleled and therefore ideally suited for this study. The results show that it is possible to detect microscopic chemical changes using PEEM-NEXAFS, specifically, oxidation at the sliding interface of a MEMS device. We observe that wear induces oxidation of the polysilicon at the immediate contact interface, and the spectra are consistent with those from amorphous SiO 2 . The oxidation is correlated with gouging and debris build-up in the wear track, as measured by AFM and scanning electron microscopy (SEM).Keywords Microscale wear Á Microelectromechanical systems (MEMS) Á Nanotractor Á Photoelectron emission microscopy (PEEM) Á Atomic force microscopy (AFM)

show abstract

Section: µMmentioning

confidence: 69%

Characterization of Microscale Wear in a Polysilicon-Based MEMS Device Using AFM and PEEM–NEXAFS Spectromicroscopy

et al. 2009

View full text Add to dashboard Cite

show abstract

“…For the SiO 2 valence band the intensity ratio between the non-bonding (O 2p) and the bonding (O 2p-Si 3p and O 2p-Si 3s) features has been reported to vary with the Si-O coordination in thin SiO 2 films, 23 and might be indicative of differences in the structural order, density and dielectric properties of the oxide material. 24 The strong similarity between the spectral features measured for the SiO 2 layers synthesized with and without graphene excludes any influence on the SiO 2 layer structure due to the presence of the graphene overlayer, in spite of the fact that on the bare Si/Ir(111) surface the oxidation rate is almost ten times faster.…”

Section: B Graphene Dopingmentioning

confidence: 86%

Chemical gating of epitaxial graphene through ultrathin oxide layers

et al. 2015

View full text Add to dashboard Cite

We achieved a controllable chemical gating of epitaxial graphene grown on metal substrates by exploiting the electrostatic polarization of ultrathin SiO2 layers synthesized below it. Intercalated oxygen diffusing through the SiO2 layer modifies the metal-oxide work function and hole dopes graphene. The graphene/oxide/metal heterostructure behaves as a gated plane capacitor with the in situ grown SiO2 layer acting as a homogeneous dielectric spacer, whose high capacity allows the Fermi level of graphene to be shifted by a few hundreds of meV when the oxygen coverage at the metal substrate is of the order of 0.5 monolayers. The hole doping can be finely tuned by controlling the amount of interfacial oxygen, as well as by adjusting the thickness of the oxide layer. After complete thermal desorption of oxygen the intrinsic doping of SiO2 supported graphene is evaluated in the absence of contaminants and adventitious adsorbates. The demonstration that the charge state of graphene can be changed by chemically modifying the buried oxide/metal interface hints at the possibility of tuning the level and sign of doping by the use of other intercalants capable of diffusing through the ultrathin porous dielectric and reach the interface with the metal.

show abstract

“…However, there is no equivalent peak in the C 1s K-edge spectrum of CNF; thus, the peak is speculated to represent a Si–O–C structure. Furthermore, the main peak of SiOC-CNF-1 is found in the XANES spectra of the O 1s K-edge at 539.8 eV, while for SiOC-CNF-2 and SiOC-CNF-3, the major peak is located at 538.4 eV, , corresponding to a silicon–oxygen octahedral or silicon–oxygen tetrahedral structure. These results reveal that the Si–O structure in SiOC is distinct from the silicon–oxygen tetrahedral structure of SiO 2 at a low POSS-NH 2 content.…”

Section: Resultsmentioning

confidence: 99%

Modulation of Si–O Structure in Uniformly Ultrasmall Silicon Oxycarbide for Superior Lifespan of Lithium Metal Anodes

Jiang,

Li,

Jiang

et al. 2023

ACS Nano

View full text Add to dashboard Cite

Utilizing nanoseeds guiding homogeneous deposition of lithium is an effective strategy to inhibit disorderly growth of lithium, where silicon oxide has been attracting attention as a transform seed. However, the research on silicon-oxide-based seeds has concentrated more on utilizing their lithiophilicity but less on their Si−O structures, which could result in different failure mechanisms. In this study, various Si−O structures of silicon oxycarbide carbon nanofibers are prepared by adjusting the content of octa(aminopropylsilsesquioxane). According to XANES and experimental observations, the C-rich SiOC has an active Si− O−C structure but generates a larger volume variation during lithiation, while in the O-rich phase, the silica−oxygen tetrahedral structure can contribute to alleviate the volume expansion but has poor electrochemical activity. SiOC, which is dominated by SiO 3 C, has a suitable Si−O and silica−oxygen tetrahedral-structure distribution, which balances the electrochemical activity and volume expansion. This allows the host to demonstrate an excellent lifespan over 3740 h with a tiny voltage hysteresis (22 mV) at 2 mA cm −2 , and it retains a favorable capacity of 97 mA h g −1 after 630 cycles with a high Coulombic efficiency of 99.7% in full cells. This study experiences the influence of various Si−O structures on lithium metal anodes.

show abstract

Enhancement of Si–O hybridization in low-temperature grown ultraviolet photo-oxidized SiO2 film observed by x-ray absorption and photoemission spectroscopy

Cited by 14 publications

References 23 publications

Characterization of Microscale Wear in a Polysilicon-Based MEMS Device Using AFM and PEEM–NEXAFS Spectromicroscopy

Characterization of Microscale Wear in a Polysilicon-Based MEMS Device Using AFM and PEEM–NEXAFS Spectromicroscopy

Chemical gating of epitaxial graphene through ultrathin oxide layers

Modulation of Si–O Structure in Uniformly Ultrasmall Silicon Oxycarbide for Superior Lifespan of Lithium Metal Anodes

Contact Info

Product

Resources

About