Influence of Oxygen Vacancies and Strain on Electronic Reliability of SiO2-x Films

2005 ◽  
Vol 864 ◽  
Author(s):  
Ken Suzuki ◽  
Yuta Ito ◽  
Hideo Miura ◽  
Tetsuo Shoji
Keyword(s):  
Molecular Dynamics ◽  
Band Gap ◽  
Quantum Chemical ◽  
Tensile Strain ◽  
Oxygen Vacancies ◽  
Structural Characteristics ◽  
Silicon Monoxide ◽  
Large Change ◽  
Dynamics Analysis ◽  
Quantum Chemical Molecular Dynamics

AbstractWe performed a quantum chemical molecular dynamics analysis for SiO2-x structure under strain to make clear the effect of the strain and intrinsic defects on both electronic and structural characteristics of SiO2-x. The SiO2-x showed a large change of the structure during the simulation. This is mainly because that the Si-O bonds near an oxygen vacancy were broken and a free silicon monoxide molecule was generated in the SiO2-x structure. The magnitude of the band gap of the SiO2-x decreased drastically due to the formation of the free monoxide. In addition, the band gap decreased further under large tensile strain of about 10%. We can conclude therefore, that both the existence of oxygen vacancies and tensile strain in SiO2-x films deteriorate the electronic reliability of the oxide film seriously.

Tight-Binding Quantum Chemical Molecular Dynamics of Oxygen Migration of Rh-supporting CeO2 Surfaces

2014 ◽  
Vol 1704 ◽  
Author(s):  
Ai Suzuki ◽  
Ryuji Miura ◽  
Nozomu Hatakeyama ◽  
Akira Miyamoto
Keyword(s):  
Molecular Dynamics ◽  
Quantum Chemical ◽  
Oxygen Vacancies ◽  
Tight Binding ◽  
Mean Square Displacement ◽  
Mean Square ◽  
Oxygen Mobility ◽  
Oxygen Migration ◽  
The Mean ◽  
Quantum Chemical Molecular Dynamics

ABSTRACTThe electronic properties of the interface between Rh clusters and CeO2 (111), (110) and (100) surfaces were studied using an isothermal-isobaric (NPT) ensemble at 773 K and 101.343 kPa using the tight binding-quantum chemical molecular dynamics (TB-QCMD) method. The amount of electronic exchange by interaction at the interface between the supported Rh55 clusters and each CeO2 surface was investigated quantitatively. A comparison of the mean square displacement (MSD) showed that the topmost oxygens on the Rh-supporting CeO2 surface exhibited higher mobility than those of the bare CeO2 surface. Although the mobility of the topmost oxygens on the bare CeO2 surface was in the order (100) > (110) > (111), this sequence was altered by the presence of Rh, so that the oxygen mobility for the more open (110) surface was the largest. The amount of electron exchange that occurred between Rh and the CeO2 (110) surface was also larger than for the (111) or (100) surface. The Ce 4f orbitals on the CeO2 (110) surface exhibited the strongest mixing with Rh 4d orbitals, which simultaneously caused restructuring and instability of the topmost Ce-O bonds. This enhancement of oxygen migration in the presence of Rh was occurred together with an increase in the number of oxygen vacancies on the ceria surface. This was because the topmost oxygens was shifted to have a stronger affinity with Rh and thus formed stronger bonds with Rh than with Ce.

Quantum Chemical Molecular Dynamics Study of the Water–Gas Shift Reaction on a Pd/MgO(100) Catalyst Surface

2013 ◽  
Vol 117 (10) ◽  
pp. 5051-5066 ◽  
Author(s):  
Farouq Ahmed ◽  
Ryuji Miura ◽  
Nozomu Hatakeyama ◽  
Hiromitsu Takaba ◽  
Akira Miyamoto ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Quantum Chemical ◽  
Catalyst Surface ◽  
Water Gas Shift ◽  
Water Gas Shift Reaction ◽  
Shift Reaction ◽  
Water Gas ◽  
Quantum Chemical Molecular Dynamics

Quantum Chemical Molecular Dynamics Simulation of the Plasma Etching Processes

2003 ◽  
Vol 42 (Part 1, No. 4B) ◽  
pp. 1859-1864 ◽  
Author(s):  
Katsumi Sasata ◽  
Toshiyuki Yokosuka ◽  
Hitoshi Kurokawa ◽  
Seiichi Takami ◽  
Momoji Kubo ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Plasma Etching ◽  
Quantum Chemical ◽  
Dynamics Simulation ◽  
Quantum Chemical Molecular Dynamics
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