Photoluminescence and Electron Spin Resonance of Silicon Dioxide Crystal with Rutile Structure (Stishovite)

TL;DR

This study investigates the photoluminescence and electron spin resonance signals in stishovite, revealing defect-related luminescence bands and complex decay kinetics influenced by impurities and thermal effects.

Contribution

It provides new insights into defect-related luminescence and decay dynamics in stishovite, a silicon dioxide crystal with rutile structure.

Findings

Identification of blue and UV luminescence bands at 3 eV and 4.75 eV.

Observation of multiple decay components with different time constants.

Detection of wave-like thermal dependencies linked to defect dynamics.

Abstract

An electron spin resonance (ESR) and photoluminescence signal is observed in the as grown single crystal of stishovite indicating the presence of defects in the non-irradiated sample. Photoluminescence of the as received stishovite single crystals exhibits two main bands - a blue at 3 eV and an UV at 4.75 eV. Luminescence is excited in the range of optical transparency of stishovite (below 8.75 eV) and, therefore, is ascribed to defects. A wide range of decay kinetics under a pulsed excitation is observed. For the blue band besides the exponential decay with a time constant of about 18 {\mu}s an additional ms component is revealed. For the UV band besides the fast component with a time constant of 1-3 ns a component with a decay in tens {\mu}s is obtained. The main components (18 {\mu}s and 1-3 ns) possess a typical intra-center transition intensity thermal quenching. The effect of the additional slow component is related to the presence of OH groups and/or carbon molecular defects modifying the luminescence center. The additional slow components exhibit wave-like thermal dependences. Photo-thermally stimulated creation-destruction of complex comprising host defect - interstitial modifiers explains slow luminescence wave-like thermal dependences.