Chemical annealing of oxygen hole centers in bulk glasses

Tandon, Pushkar

doi:10.1016/j.jnoncrysol.2004.02.001

Cited by 6 publications

(4 citation statements)

References 23 publications

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“…(2.1), here both the E´-center and NBOHC can form in dry oxide layers. In wet SiO 2 , hydrogen diffuses through the network and simultaneously undergoes reactions with the NBOHC during the first seconds of irradiation (destructive mode of NBOHC) followed by a slow creation mode [Tandon 2004]. This decay process is attributable to the simultaneous recombination of NBOHC with dissociated hydrogenous species, eq.…”

Section: Dose-temperature Effectmentioning

confidence: 99%

Silicon Nanocluster in Silicon Dioxide: Cathodoluminescence, Energy Dispersive X-Ray Analysis and Infrared Spectroscopy Studies

Salh¹

2011

Crystalline Silicon - Properties and Uses

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This chapter is extended to various electronical and optical modifications of amorphous silica (a-SiO 2) layers as they are applied in microelectronics, optoelectronics, as well as in the forthcoming photonics. Scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FTIR) and cathodoluminescence (CL) have been used to investigate thermally grown pure amorphous silicon dioxide and ion-implanted layers with thickness d ox =100-500 nm. The main luminescent centers in silicon dioxide layers are the red luminescence (650 nm; 1.85 eV) of the non-bridging oxygen hole center (NBOHC; ≡Si-O•), a blue (460 nm; 2.7 eV) and a ultra violet luminescence (290 nm; 4.3 eV) of the oxygen deficient centers (ODC's; ≡Si•••Si≡), and a yellow luminescence (570 nm; 2.2 eV) appears especially in hydrogen treated silica indicating water molecules, and on the other hand, in silicon excess samples indicating higher silicon aggregates. A quite different CL dose behavior of the red luminescence is observed in dry and hydrogen-treated samples due to dissociation and re-association of mobile hydrogen and oxygen to radicals of the silica network. Additionally implanted hydrogen diminishes the red luminescence in wet oxide but maintains the blue and the UV bands. Thus hydrogen passivates the NBOHC and keeps the ODC's in active emission states. A model of luminescence center transformation is proposed based on radiolytic dissociation and re-association of mobile oxygen and hydrogen at the centers as well as formation of interstitial H 2 , O 2 , and H 2 O molecules. Non-stoichiometric SiO x layers produced by direct ion implantation or reactive sputtering are used to investigate whether the different luminescent centers are related to oxygen or to silicon. Oxygen implantation as well as direct silicon implantation led to an oxygen surplus as well as an oxygen deficit, respectively. The related luminescence damages provide direct evidence to the nature of the defects. Oxygen-deficient thin silica layers SiO x with different stoichiometric degree 1≤x≤2, were prepared by thermal evaporation of silicon monoxide in vacuum and in ambient oxygen atmosphere of varying pressure onto crystalline silicon substrates. The chemical composition has been calibrated and determined by FTIR spectroscopy. The CL spectra of the oxygen-deficient layers shows the development of typical silica luminescence bands at the composition threshold x≤1.5 onwards to x=2. The

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Section: Dose-temperature Effectmentioning

confidence: 99%

Silicon Nanocluster in Silicon Dioxide: Cathodoluminescence, Energy Dispersive X-Ray Analysis and Infrared Spectroscopy Studies

Salh¹

2011

Crystalline Silicon - Properties and Uses

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“…(3), here both the E´center and NBOHC can form in dry oxide layers. In wet SiO 2 , hydrogen diffuses through the network and simultaneously undergoes reactions with the NBOHC during the first seconds of irradiation (destructive mode of NBOHC) followed by a slow creation mode [8]. This decay process is attributable to the simultaneous recombination of NBOHC with dissociated hydrogenous species, Eq.…”

Section: Resultsmentioning

confidence: 99%

Mechanism of radiation‐induced defects in SiO₂: The role of hydrogen

Salh

Fitting

2007

Phys. Status Solidi (c)

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Hydrogen related defects in anhydrous "dry", hydrated "wet" and hydrogen implanted amorphous silicon dioxide (a-SiO 2 ) layers are investigated using cathodoluminescence (CL) technique in a wave length range 200-800 nm at specimen temperatures between room and liquid nitrogen temperature. Particular defect centers have been identified including the non-bridging oxygen hole center (NBOHC) associated with the red luminescence at 650 nm (1.9 eV) and the oxygen deficient centers (ODCs) with the blue (460 nm; 2.7 eV) and UV band (290 nm; 4.3 eV). An additional luminescence band Y in the greenyellow region has been clearly detected in hydrogen-implanted as well as in oxygen-deficient samples. The red luminescence shows quite different CL dose behavior in wet and hydrogen-treated samples due to dissociation and re-association of mobile hydrogen and oxygen from and to the NBOHC. The yellow luminescence at 580 nm (2.1 eV) is discussed in terms of radiolytic water dissociation as well as of ODC's in form of small silicon aggregates in the silica matrix.

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“…Exploiting the fast kinetics and large equilibrium constant for hydrogen reaction with some of the oxygen hole centers (such as peroxy radical and non‐bridging oxygen defect), Tandon 28 has solved the reaction–diffusion problem and established the precise correlation between the effective diffusivity and intrinsic diffusivity of hydrogen in bulk glasses, as a function of hydrogen and defect concentrations. The effective hydrogen diffusivity is predicted to be: 28 where D eff and D H2 are the effective and intrinsic diffusivity of hydrogen, and C Defect and D H2 are the concentration of the reactive defects and hydrogen respectively. The above expression when used to estimate the chemical annealing rate of defects in bulk glasses results in predictions 28 that are in very good agreement (Fig.…”

Section: Technical Discussionmentioning

confidence: 99%

“…The effective hydrogen diffusivity is predicted to be: 28 where D eff and D H2 are the effective and intrinsic diffusivity of hydrogen, and C Defect and D H2 are the concentration of the reactive defects and hydrogen respectively. The above expression when used to estimate the chemical annealing rate of defects in bulk glasses results in predictions 28 that are in very good agreement (Fig. 13) with the experimental observations of Shelby 29 over a broad range of conditions.…”

Section: Technical Discussionmentioning

confidence: 99%

Fundamental Understanding of Processes Involved in Optical Fiber Manufacturing Using Outside Vapor Deposition Method

Tandon¹

2005

Int J Applied Ceramic Tech

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Optical fibers are often made using a flame hydrolysis deposition process, in which silica and doped silica particles from a soot‐laden flame are deposited on a target rod. The porous preforms thus formed are subsequently sintered into glass blanks and then drawn into optical fiber. We review here various tools that have been developed for better understanding of different processes involved in the making of optical fibers using the outside vapor deposition technique. Fundamental understanding of the different unit operations involved in the optical fiber manufacturing is critical for process optimization and improved product attributes.

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Chemical annealing of oxygen hole centers in bulk glasses

Cited by 6 publications

References 23 publications

Silicon Nanocluster in Silicon Dioxide: Cathodoluminescence, Energy Dispersive X-Ray Analysis and Infrared Spectroscopy Studies

Silicon Nanocluster in Silicon Dioxide: Cathodoluminescence, Energy Dispersive X-Ray Analysis and Infrared Spectroscopy Studies

Mechanism of radiation‐induced defects in SiO₂: The role of hydrogen

Fundamental Understanding of Processes Involved in Optical Fiber Manufacturing Using Outside Vapor Deposition Method

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Chemical annealing of oxygen hole centers in bulk glasses

Cited by 6 publications

References 23 publications

Silicon Nanocluster in Silicon Dioxide: Cathodoluminescence, Energy Dispersive X-Ray Analysis and Infrared Spectroscopy Studies

Silicon Nanocluster in Silicon Dioxide: Cathodoluminescence, Energy Dispersive X-Ray Analysis and Infrared Spectroscopy Studies

Mechanism of radiation‐induced defects in SiO2: The role of hydrogen

Fundamental Understanding of Processes Involved in Optical Fiber Manufacturing Using Outside Vapor Deposition Method

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Product

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Mechanism of radiation‐induced defects in SiO₂: The role of hydrogen