• Title/Summary/Keyword: missing dimer

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Early stage of heteroepitaxial Ge growth on Si(100) substrate with surface treatments using inductively coupled plasma (ICP) (ICP 표면 처리된 Si 기판 위에 성장된 Ge 층의 초기 성장 상태 연구)

  • Yang, Hyun-Duk;Kil, Yeon-Ho;Shim, Kyu-Hwan;Choi, Chel-Jong
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.21 no.4
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    • pp.153-157
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    • 2011
  • We have investigated the effect of inductively coupled plasma (ICP) treatment on the early growth stage of heteroepitaxial Ge layers grown on Si(100) substrates using low pressure chemical vapor deposition (LPCVD), The Si(100) substrates were treated by ICP process with various source and bias powers, followed by the Ge deposition, The ICP treatment led to the enhancement in the coalescence of Ge islands, The growth rate of Ge on Si(100) with ICP surface treatment is about 5 times higher than that without ICP surface treatment. A missing dimer caused by the ICP surface treatment can act as a nucleation site for Ge adatoms, which could be responsible for the improvement in growth behavior of Ge on Si(100) substrates.

Two kinds of defects existing on Si(5 5 12)-$2{\times}1$

  • Duvjir, Ganbat;Kim, Hi-Dong;Duvjir, Otgonbayar;Seo, Jae-M.
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.02a
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    • pp.364-364
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    • 2010
  • Defects existing on the clean Si(5 5 12)-$2{\times}1$, composed of one-dimensional(1-D) structures such as honeycomb (H) chain, $\pi$-bonded ($\pi$) chains, dimer-adatom (D-A) row, and tetramer (T) row, have been investigated by scanning tunneling microscopy (STM). It is found that the defects can be classified to two categories: One is originated from phase boundaries in D-A and T rows having $2{\times}$ periodicities, by which buckling directions are reversed, and the other is caused by missing atoms on $\pi$ chains, D-A rows, and T rows. All these defects are symmetric with respect to the [6 6 $\bar{5}$] direction, which is due to one-dimensional symmetry along the [1 $\bar{1}$ 0] direction. Especially it is worth noticing that on H chains none of such defects exist, which implies that the H chain is energetically the most stable among 1-D structures existing on Si(5 5 12)-$2{\times}1$.

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Inactivation of Brain myo-Inositol Monophosphate Phosphatase by Pyridoxal-5'-Phosphate

  • Kim, Dae-Won;Hong, Joung-Woo;Eum, Won-Sik;Choi, Hee-Soon;Choi, Soo-Hyun;Kim, So-Young;Lee, Byung-Ryong;An, Jae-Jin;Lee, Sun-Hwa;Lee, Seung-Ree;Kwon, Oh-Shin;Kwon, Hyeok-Yil;Cho, Sung-Woo;Lee, Kil-Soo;Park, Jin-Seu;Choi, Soo-Young
    • BMB Reports
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    • v.38 no.1
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    • pp.58-64
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    • 2005
  • Myo-inositol monophosphate phosphatase (IMPP) is a key enzyme in the phosphoinositide cell-signaling system. This study found that incubating the IMPP from a porcine brain with pyridoxal-5'-phosphate (PLP) resulted in a time-dependent enzymatic inactivation. Spectral evidence showed that the inactivation proceeds via the formation of a Schiff's base with the amino groups of the enzyme. After the sodium borohydride reduction of the inactivated enzyme, it was observed that 1.8 mol phosphopyridoxyl residues per mole of the enzyme dimer were incorporated. The substrate, myo-inositol-1-phosphate, protected the enzyme against inactivation by PLP. After tryptic digestion of the enzyme modified with PLP, a radioactive peptide absorbing at 210 nm was isolated by reverse-phase HPLC. Amino acid sequencing of the peptide identified a portion of the PLP-binding site as being the region containing the sequence L-Q-V-S-Q-Q-E-D-I-T-X, where X indicates that phenylthiohydantoin amino acid could not be assigned. However, the result of amino acid composition of the peptide indicated that the missing residue could be designated as a phosphopyridoxyl lysine. This suggests that the catalytic function of IMPP is modulated by the binding of PLP to a specific lysyl residue at or near its substrate-binding site of the protein.