Unexploited Information from Luminescence Spectra
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Abstract
Luminescence is a highly sensitive technique to monitor the presence of impurities, imperfections and lattice
distortions. To fully exploit it requires sensitive detection systems with high resolution spectral data and
temperature control. This review notes both how detector technology has advanced, and mentions simple routes
to generate more efficient use of existing photomultipliers. Modern detectors enable wavelength multiplexed
spectrometer systems, which are prerequisites for both detailed thermoluminescence analyses and newer
applications. These include recording the spectral changes from different crystalline phases, and capturing their
characteristic intensity signatures at the phase transition temperature. Less expected is that the luminescence
intensity is strongly influenced by the presence of impurities, even when they are not dispersed in the host lattice,
but are grouped as nanoparticle inclusions. Spectacular host intensity changes can occur when the inclusions
undergo phase transitions. Luminescence is also frequently used to monitor ion implanted materials, but for
examples reported here, the spectra can be seriously distorted by absorption and reflectivity properties of the
implant layer. Further, luminescence data have demonstrated that the underlying host material can be stressed and
then relax into new structural phases. These aspects of spectral distortion and lattice relaxations may be far more
common than has been noted in the previous literature. Finally, because the techniques are multi-disciplinary, brief
mentions of systematic errors in signal analysis are noted.