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DY: Dynamik und Statistische Physik

DY 36: Glasses II (joint session DF/DY)

DY 36.7: Vortrag

Montag, 7. März 2005, 15:45–16:00, TU A060

Cathodoluminescence of Hydrogen-related Defects in SiO₂ Layers — •Roushdey Salh, Andreas von Czarnowski, and Hans-Joachim Fitting — Institute of Physics, University of Rostock, Universitätsplatz 3, D-18051 Rostock

Hydrogen related defects in anhydrous "dry", hydrated "wet" and hydrogen implanted amorphous silicon dioxide (a-SiO₂) layers are investigated using scanning electron microscopy (SEM) and cathodoluminescence (CL) techniques in a wave length range λ=200-800 nm at specimen temperatures between room and liquid nitrogen temperature. Particular luminescent defect centers have been identified including the non-bridging oxygen hole center (NBOHC) associated with the red luminescence at 650 nm (1.9 eV), the oxygen deficient centers (ODC) with the blue (460 nm ; 2.7 eV) and the ultraviolet (295 nm ; 4.2 eV) bands and a yellow luminescence band at 580 nm (2.1 eV) associated with the self trapped exciton (STE) or a water state in the silicon dioxide network. The dose behavior of the red (R) luminescence in wet and dry oxide is quite different, decreasing in wet oxide from a high initial level and increasing in dry oxide from almost zero at room temperature. Additionally implanted hydrogen diminishes the red luminescence but increases the blue and the UV bands. Thus hydrogen passivates the NBOHC and keeps the ODC’s in active emission state. A preliminary model of luminescence center transformation is based on radiolytic dissociation and re-association of mobile oxygen and hydrogen at the centers as well as formation of interstitial H₂, O₂, and H₂O molecules.