Structural defect control and photosensitivity in reactively sputtered germanosilicate glass films

Conference · Sat Feb 01 04:00:00 EST 1997

OSTI ID:431159

Potter, Jr, B G; Simmons-Potter, K; Warren, W L; Ruffner, J A ^[1]

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1. and others

The optical performance of refractive index structures induced in photosensitive (PS) glasses ultimately depends on the index modulation depth attainable. In germanosilicate materials, the photosensitive response is linked to the presence of oxygen-deficient germanium point defect centers. Prior efforts to increase PS in these materials, e.g., hydrogen loading, rely on a chemical reduction of the glass structure to enhance the population of oxygen deficient centers and thus increase the saturated refractive index change. We have previously reported the development of highly photosensitive, as-deposited germanosilicate glass films through reactive atmosphere (O{sub 2}/Ar) sputtering from a Ge/Si alloy target. The present work details our investigation of the effect of substrate temperature during deposition on the material structure and propensity for photosensitivity. Using optical absorption/bleaching, Raman, electron paramagnetic resonance (EPR) and selective charge injection techniques we show that the predominate defect states responsible for the PS response can be varied through substrate temperature control. We find that two regimes of photosensitive behavior can be accessed which exhibit dramatically different uv-bleaching characteristics. Thus, the corresponding dispersion of the refractive index change as well as its magnitude can be controlled using our synthesis technique. Tentative defect models for the photosensitive process in materials deposited at both ambient temperature and at elevated substrate temperatures will be presented.

• Research Organization: Sandia National Labs., Albuquerque, NM (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 431159
• Report Number(s): SAND--96-2997C; CONF-970231--3; ON: DE97001872
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
GERMANIUM OXIDES
GLASS
PHOTOSENSITIVITY
POINT DEFECTS
REFRACTIVE INDEX
SILICATES