Optical properties of Ge-oxygen defect center embedded in silica films

TL;DR

This study investigates the optical properties of Ge-oxygen defect centers in silica films, revealing how the matrix environment influences their luminescence and intersystem crossing efficiency across a range of temperatures.

Contribution

It provides new insights into the emission spectra and decay dynamics of Ge-oxygen defect centers in silica films, highlighting the matrix-dependent efficiency of intersystem crossing.

Findings

Two luminescence bands at 4.3 eV and 3.2 eV linked to singlet and triplet states.

Intersystem crossing rate is more efficient in silica films than in bulk.

Temperature-dependent emission spectra observed from 10 to 300 K.

Abstract

The photo-luminescence features of Ge-oxygen defect centers in a 100nm thick Ge-doped silica film on a pure silica substrate were investigated by looking at the emission spectra and time decay detected under synchrotron radiation excitation in the 10-300 K temperature range. This center exhibits two luminescence bands centered at 4.3eV and 3.2eV associated with its de-excitation from singlet (S1) and triplet (T1) states, respectively, that are linked by an intersystem crossing process. The comparison with results obtained from a bulk Ge-doped silica sample evidences that the efficiency of the intersystem crossing rate depends on the properties of the matrix embedding the Ge-oxygen defect centers, being more effective in the film than in the bulk counterpart.