Trapping and Recombination Centers in Cesium Hafnium Chloride Single Crystals

Authors

M. Buryi, R. Král, V. Babin, J. Páterek, V. Vaněček, P. Veverka, M. Kohoutková, V. Laguta, M. Fasoli, I. Villa, F. Cova, A. Vedda, M. Nikl

Laboratory / Department
Department of Optical Materials
Citation
Journal of Physical Chemistry C 123 (2019) 19402-19411.
DOI
10.1021/acs.jpcc.9b05760
Year
2019

Charge trapping phenomena and recombination centers were studied in three Cs2HfCl6 single crystals of slightly different stoichiometry grown by the vertical Bridgeman method. Electron paramagnetic resonance (EPR) spectra measured both before and after X-ray irradiation show creation of two distinct Vk centers. One of them was Vk(a) already known from a recent work. The second Vk center presently observed has never been described before. Its existence at an almost undetectable level was observed only in two of the three crystals.

Dept27_VVFig1.png
Illustration of a change in the shape of the emission spectrum with increasing temperature, a photography of a crystal under UV radiation and an EPR signal coming from a newly discovered Vk center