We analyze Ge-related defects in Ge-doped SiO2 using first-principles density functional techniques. Ge is incorporated at the level of ;1 mol% and above. The growth conditions of Ge:SiO2 naturally set up an oxygen deficiency relative to undoped SiO2, with vacancy concentrations increasing by a factor of 105 and O vacancies binding strongly to Ge impurities. All the centers considered exhibit potentially EPR-active states, candidates for identification as the Ge(n) centers. Substitutional Ge produces an apparent gap shrinking via its extrinsic levels.
Stability of Ge-related point defects and complexes in Ge-doped SiO2
CARBONARO, CARLO MARIA;FIORENTINI, VINCENZO;BERNARDINI, FABIO
2002-01-01
Abstract
We analyze Ge-related defects in Ge-doped SiO2 using first-principles density functional techniques. Ge is incorporated at the level of ;1 mol% and above. The growth conditions of Ge:SiO2 naturally set up an oxygen deficiency relative to undoped SiO2, with vacancy concentrations increasing by a factor of 105 and O vacancies binding strongly to Ge impurities. All the centers considered exhibit potentially EPR-active states, candidates for identification as the Ge(n) centers. Substitutional Ge produces an apparent gap shrinking via its extrinsic levels.
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