scholarly journals Identification of electron and hole traps in lithium tetraborate (Li2B4O7) crystals: Oxygen vacancies and lithium vacancies

2010 ◽  
Vol 107 (11) ◽  
pp. 113715 ◽  
Author(s):  
M. W. Swinney ◽  
J. W. McClory ◽  
J. C. Petrosky ◽  
A. T. Brant ◽  
V. T. Adamiv ◽  
...  
Keyword(s):  
Oxygen Vacancies ◽  
Lithium Tetraborate ◽  
Electron And Hole Traps

Trap State Photoluminescence of Nanocrystalline and Bulk TiO2,: Implications for Carrier Transport

2010 ◽  
Vol 1268 ◽  
Author(s):  
Jeanne Louise McHale ◽  
Christopher C. Rich ◽  
Fritz J. Knorr
Keyword(s):  
Carrier Transport ◽  
Oxygen Vacancies ◽  
Surface Defects ◽  
Vacuum Annealing ◽  
Bulk Crystals ◽  
Trap State ◽  
Surface Binding ◽  
Binding Agents ◽  
Electron And Hole Traps ◽  
Molecular Nature

AbstractThe visible photoluminescence of nanocrystalline TiO2 is examined in the presence of surface binding agents and as a function of vacuum annealing in order to probe the molecular nature of surface defects. The photoluminesence (PL) of bulk crystals of anatase TiO2 from (101) and (001) planes is also reported in order to test the hypothesis that electron and hole traps are spatially isolated on different crystal planes. We find that a number of hole scavengers are capable of quenching the PL associated with trapped electrons, while the ability of oxygen to quench PL through electron scavenging varies with the nature of the sample. We conclude that hole scavengers exert their influence on the PL through reaction with valence band holes rather than with spatially isolated trapped holes. Scavenging of electrons by O2, on the other hand, depends on adsorption at oxygen vacancies and varies with TiO2 sample.

On the origin of defect states in calcium tungstate

1969 ◽  
Vol 47 (4) ◽  
pp. 463-471 ◽  
Author(s):  
M. Sayer ◽  
A. D. Souder
Keyword(s):  
Ionizing Radiation ◽  
Single Crystals ◽  
Oxygen Vacancies ◽  
Excitation Mechanism ◽  
Defect States ◽  
Thermally Stimulated Current ◽  
Calcium Tungstate ◽  
Monovalent Ions ◽  
Monovalent Ion ◽  
Electron And Hole Traps

A comparison has been made of thermoluminescence and thermally stimulated current in single crystals of calcium tungstate either doped with impurities or nominally pure but excited by ionizing radiation. Both effects were large in the case of monovalent impurities with glow peaks near 260 °K being characteristic of the impurity and peaks near 160 °K arising from an enhancement of a structure which normally results from radiation damage. Trivalent impurities had a lesser effect with the production of glow peaks near 300 °K. The structures responsible for the prominent glow peaks are suggested to be: 260 °K—monovalent ions in calcium sites, 154/160 °K—oxygen vacancies associated with either a W5+ or a monovalent ion at a calcium site, 300 °K—calcium vacancies. The occupancy of electron and hole traps is found to be related. This relationship is used to deduce information regarding the excitation mechanism for free holes and electrons in calcium tungstate.

scholarly journals Electron and hole traps in Ag-doped lithium tetraborate (Li2B4O7) crystals

2011 ◽  
Vol 110 (9) ◽  
pp. 093719 ◽  
Author(s):  
A. T. Brant ◽  
B. E. Kananan ◽  
M. K. Murari ◽  
J. W. McClory ◽  
J. C. Petrosky ◽  
...  
Keyword(s):  
Lithium Tetraborate ◽  
Electron And Hole Traps

Conditions for atomic imaging of mullite

1989 ◽  
Vol 47 ◽  
pp. 418-419
Author(s):  
T. A. Epicier ◽  
G. Thomas
Keyword(s):  
Oxygen Vacancies ◽  
High Resolution Electron Microscopy ◽  
Ceramic Materials ◽  
Work Conditions ◽  
Real Space ◽  
Potential Candidate ◽  
Silicate Mineral ◽  
Resolution Electron ◽  
The Subject ◽  
Aluminium Silicate

Mullite is an aluminium-silicate mineral of current interest since it is a potential candidate for high temperature applications in the ceramic materials field.In the present work, conditions under which the structure of mullite can be optimally imaged by means of High Resolution Electron Microscopy (HREM) have been investigated. Special reference is made to the Atomic Resolution Microscope at Berkeley which allows real space information up to ≈ 0.17 nm to be directly transferred; numerous multislice calculations (conducted with the CEMPAS programs) as well as extensive experimental through-focus series taken from a commercial “3:2” mullite at 800 kV clearly show that a resolution of at least 0.19 nm is required if one wants to get a straightforward confirmation of atomic models of mullite, which is known to undergo non-stoichiometry associated with the presence of oxygen vacancies.Indeed the composition of mullite ranges from approximatively 3Al2O3-2SiO2 (referred here as 3:2-mullite) to 2Al2O3-1SiO2, and its structure is still the subject of refinements (see, for example, refs. 4, 5, 6).

Investigation of Some Characterizations of Black TiO\(_2\) Nanotubes Via Spectroscopic Methods

2019 ◽  
Vol 29 (2) ◽  
pp. 189 ◽  
Author(s):  
Tho Truong Nguyen ◽  
Thi Minh Cao ◽  
Hieu Van Le ◽  
Viet Van Pham
Keyword(s):  
Water Splitting ◽  
Oxygen Vacancies ◽  
Light Response ◽  
Nanotube Arrays ◽  
Spectroscopic Methods ◽  
Visible Light Response ◽  
Uv Visible ◽  
Visible Reflectance ◽  
Splitting Effect ◽  
Anodization Method

The black TiO\(_2\) with substantial Ti\(^3+\) and oxygen vacancies exhibit an excellent photoelectrochemical water-splitting performance due to the improved charge transport the extended visible light response. In this study, black TiO\(_2\) nanotube arrays synthesized by the anodization method, and then, they have been investigated some characterizations by spectroscopic methods such as UV-visible reflectance (UV-vis DRS), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, and photoluminescence spectrum. The results showed that some highlighted properties of the black TiO2 nanotube arrays and they could apply for water-splitting effect.

Oxygen Vacancies in Zirconium Oxide as the Blue Luminescence Centers and Traps Responsible for Charge Transport

2020 ◽  
Author(s):  
Damir R. Islamov ◽  
Vladimir A. Gritsenko ◽  
Timofey V. Perevalov ◽  
Vladimir Sh. Aliev ◽  
Alexander P. Yelisseyev ◽  
...  
Keyword(s):  
Charge Transport ◽  
Zirconium Oxide ◽  
Oxygen Vacancies ◽  
Blue Luminescence ◽  
Luminescence Centers

Oxidized indium with transformable dimensions for CO2 electroreduction toward formate aided by oxygen vacancies

2020 ◽  
Vol 4 (7) ◽  
pp. 3726-3731
Author(s):  
Fenghui Ye ◽  
Jinghui Gao ◽  
Yilin Chen ◽  
Yunming Fang
Keyword(s):  
Crucial Role ◽  
Oxygen Vacancies ◽  
Value Added ◽  
Promising Technique ◽  
Co2 Electroreduction ◽  
Value Added Products

Electroreduction of CO2 into value-added products is a promising technique in which the structure of the catalyst plays a crucial role.

CeO2 Nanostructures Enriched with Oxygen Vacancies for Photocatalytic CO2 Reduction

2019 ◽  
Vol 3 (1) ◽  
pp. 138-148 ◽  
Author(s):  
Abdo Hezam ◽  
Keerthiraj Namratha ◽  
Q. A. Drmosh ◽  
Deepalekshmi Ponnamma ◽  
Jingwei Wang ◽  
...  
Keyword(s):  
Oxygen Vacancies ◽  
Co2 Reduction

Effects of Oxygen Vacancies and Cation Valence States on the Triboelectric Property of Substoichiometric Oxide Films

2021 ◽  
Author(s):  
Yongqiao Zhu ◽  
Shiquan Lin ◽  
Wenchao Gao ◽  
Miao Zhang ◽  
Chaogui Yang ◽  
...  
Keyword(s):  
Oxygen Vacancies ◽  
Oxide Films ◽  
Valence States
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