Diffusion of cesium ion in SiO sub 2 films derived from sol-gel precursors

Journal Article · · Chemistry of Materials; (United States)

OSTI ID:5481472

Schutte, C L ^[1]; Whitesides, G M ^[2]

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1. Harvard Univ., Cambridge, MA (USA) Massachusetts Institute of Technology, Cambridge (USA)
2. Harvard Univ., Cambridge, MA (USA)

Hydrolyzed tetraethylorthosilicate (TEOS) formed SiO{sub 2} gel films after being spin-coated onto silicon substrates and heated to temperatures ranging between 200 and 800{degree}C to effect different degrees of transformation from gel to glass. The index of refraction of the films increased from 1.42 at 25{degree}C to 1.45 after thermal treatment at 800{degree}C; the thickness of the films decreased by 29 {plus minus} 6%. These thermally pretreated gels were coated with a second film of sol-gel-derived SiO{sub 2} doped with cesium chloride. Diffusion of the cesium ion through the undoped SiO{sub 2} gels was studied by measurement of the depth profile of cesium by Rutherford backscattering spectroscopy. Increasing the temperature to which the undoped layer had been exposed decreased the extent of its infiltration or diffusion by cesium at room temperature. Diffusion of cesium at high temperature ({ge}750{degree}C) was, however, independent of the thermal history of the undoped layer, indicating that the rate at which the silica film transforms from gel to glass is faster than that at which cesium diffuses.

• OSTI ID: 5481472
• Journal Information: Chemistry of Materials; (United States), Journal Name: Chemistry of Materials; (United States) Vol. 2:5; ISSN CMATE; ISSN 0897-4756
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360201* -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
CESIUM IONS
CHALCOGENIDES
CHARGED PARTICLES
CHEMICAL PREPARATION
DATA
DIFFUSION
EXPERIMENTAL DATA
FILMS
INFORMATION
IONS
MEASURING METHODS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
SILICON COMPOUNDS
SILICON OXIDES
SOL-GEL PROCESS
SYNTHESIS
THIN FILMS