Published Papers - ODA Masato

Electronic Structures Calculation of Si1-xSnx Compound Alloy Using Inter-acting Quasi-band Model

Masato Oda, Yukina Kuroda, Ayaka Kishi, Yuzo Shinozuka （Part： Lead author,　Corresponding author )

2016 COMPOUND SEMICONDUCTOR WEEK (CSW) INCLUDES 28TH INTERNATIONAL CONFERENCE ON INDIUM PHOSPHIDE & RELATED MATERIALS (IPRM) & 43RD INTERNATIONAL SYMPOSIUM ON COMPOUND SEMICONDUCTORS (ISCS) ( IEEE )    2016  [Refereed]

Interacting quasi-band model for electronic states in compound semiconductor alloys: Zincblende structure

Yuzo Shinozuka, Masato Oda

JAPANESE JOURNAL OF APPLIED PHYSICS ( IOP PUBLISHING LTD )  54 ( 9 ) 091202   2015.09  [Refereed]

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The interacting quasi-band model proposed for electronic states in simple alloys is extended for compound semiconductor alloys with general lattice structures containing several atoms per unit cell. Using a tight-binding model, a variational electronic wave function for quasi-Bloch states yields a non-Hermitian Hamiltonian matrix characterized by matrix elements of constituent crystals and concentration of constituents. Solving secular equations for each k-state yields the alloy's energy spectrum for any type of randomness and arbitrary concentration. The theory is used to address III-V (II-VI) alloys with a zincblende lattice with crystal band structures well represented by the sp(3)s* model. Using the resulting 15 x 15 matrix, the concentration dependence of valence and conduction bands is calculated in a unified scheme for typical alloys: Al1-xGaxAs, GaAs1-xPx, and GaSb1-xPx. Results agree well with experiments and are discussed with respect to the concentration dependence, direct-indirect gap transition, and band-gap-bowing origin. (C) 2015 The Japan Society of Applied Physics

DOI

Evaluation of Stretching Properties of [7]Thiaheterohelicene Framework Called "Molecular Spring" Using AFM Force Measurements and Electrostatic State Calculations

Yoshio Nakahara, Minako Higashi, Ryoto Funayama, Yasuo Horii, Hideji Osuga, Hidefumi Sakamoto, Masato Oda, Shinpei Kado, Keiichi Kimura

BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN ( CHEMICAL SOC JAPAN )  88 ( 4 ) 544 - 550   2015.04  [Refereed]

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The stretching properties of a [7]thiaheterohelicene framework, what we call molecular spring, have not been investigated so far, despite a variety of [7]thiaheterohelicene derivatives having very interesting characteristics due to both the rigidity arising from fused benzene rings and the flexibility like a spring originating from helical structure. In this study, a novel [7]thiaheterohelicene derivative, which has a disulfide moiety for bonding to a gold-coated substrate and a carboxy group for reacting with an amino-modified probe tip at each of its end groups, was synthesized in order to elucidate the elasticity of the [7]thiaheterohelicene framework by atomic force microscopy (AFM). The AFM force measurements were carried out using two carboxy-terminated disulfide derivatives with or without a [7]thiaheterohelicene moiety, and the deviation between two kinds of force-extension curves was related to the stretching originating from the [7]thiaheterohelicene framework here. Furthermore, its elasticity was compared to that of biphenyl, which is generally known as a rigid framework, using electrostatic state calculations.

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Electronic states of a lipid membrane reinforced with siloxane bond

Satofumi Yabushita, Masato Oda, Yuzo Shinozuka （Part： Corresponding author )

e-Journal of Surface Science and Nanotechnology ( Surface Science Society of Japan )  12   112 - 114   2014.03  [Refereed]

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We investigate the electronic states of a simple model of a lipid bilayer membrane with a siloxane-bond-reinforced surface using first-principles calculations based on density functional theory. Our model is a simple representation of a cerasome, a material that has proved promising as a drug delivery medium. Analyzing the electronic density of states reveals that there is a mid-gap state originating from the Si-C antibonding state. The existence of an antibonding state at mid-gap indicates that we can selectively excite an electron to this state and thus break up the siloxane network.© 2014 Landes Bioscience.

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Origin of electronic transport of lithium phthalocyanine iodine crystal

Noritake Koike, Masato Oda, Yuzo Shinozuka （Part： Corresponding author )

AIP Conference Proceedings ( American Institute of Physics Inc. )  1566   183 - 184   2013  [Refereed]

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The electronic structures of Lithium Phthalocyanine Iodine are investigated using density functional theory. Comparing the band structures of several model crystals, the metallic conductivity of highly doped LiPcIx can be explained by the band of doped iodine. These results reveal that there is a new mechanism for electronic transport of doped organic semiconductors that the dopant band plays the main role. © 2013 AIP Publishing LLC.

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Energy-Level Alignment, Ionization, and Stability of Bio-Amino Acids at Amino Acid/Si Junctions

Masato Oda, Takashi Nakayama

JAPANESE JOURNAL OF APPLIED PHYSICS ( JAPAN SOCIETY APPLIED PHYSICS )  47 ( 5 ) 3712 - 3718   2008.05  [Refereed]

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The electronic structures of 20 bio-amino acids and amino acid/Si junctions are studied using ab initio calculations. It is shown that the amino acids can be classified into two groups depending on where the highest occupied molecular orbital (HOMO) state is localized. This classification is possible owing to the molecular structural geometry and the constituent atoms in the residue part of amino acids. Moreover, we found that, owing to the hybridization of electronic states between amino acids and Si substrate, the optical transition from the HOMO state of the amino acid to the conduction band states of Si becomes possible at the amino acid/Si interface. This result indicates the possibility of the optical ionization of amino acid by producing amino acid/semiconductor junctions. The present results provide basic data not only for the microscopic understanding of protein electronic structures but also for the electronic design of new protein functions. [DOI: 10.1143/JJAP.47.3712]

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Charge injection from Si substrate into amino acids

Masato Oda, Takashi Nakayama

JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS ( INST PURE APPLIED PHYSICS )  45 ( 11 ) 8939 - 8942   2006.11  [Refereed]

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The electronic structures of amino acids on Si(I 11) surfaces are investigated using ab initio Hartree-Fock calculations. It is shown that six amino acids can be positively ionized when hole carriers are supplied to the Si substrate by transferring the hole charge from the Si substrate into an amino acid. This result indicates that the ionization of an amino acid, which activates protein functions, can be controlled electrically by producing amino-acid/Si junctions.

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Electronic-state control of amino acids on semiconductor surfaces

M Oda, T Nakayama

APPLIED SURFACE SCIENCE ( ELSEVIER SCIENCE BV )  244 ( 1-4 ) 627 - 630   2005.05  [Refereed]

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Electronic structures of amino acids on the Si(1 1 1) surfaces are investigated by using ab initio Hartree-Fock calculations. It is shown that among various polar amino acids, a histidine is the only one that can be positively ionized when hole carriers are supplied in the Si substrate, by transferring the hole charge from Si substrate to an amino acid. This result indicates that the ionization of a histidine, which will activate the protein functions, can be controlled electrically by producing amino acid/Si junctions. (c) 2004 Published by Elsevier B.V.

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3P327 Control of protein function by injecting carriers from semiconductor

Oda M., Nakayama T.

Seibutsu Butsuri ( The Biophysical Society of Japan General Incorporated Association )  45   S285   2005

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2P318 Control of protein function on semicon-ductor surfaces

Oda M., Nakayama T.

Seibutsu Butsuri ( The Biophysical Society of Japan General Incorporated Association )  44   S189   2004

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