Optical and luminescence characterization of LiBaAlF6 single crystals

• We studied electronic structure properties of undoped LiBaAlF6 single crystals.
• The VIS–UV spectrum of the refraction index was determined.
• PLE spectra were studied for both the excitonic and fast VUV emissions at 10 K.
• The low-energy tail of the host absorption was derived through PLE modeling.
• PCL was used to characterize the core-valence transitions F− 2p → Ba2+ 5p.

Far ultraviolet optical, luminescence excitation and pulse cathodoluminescence spectroscopy methods were used to determine the electronic structure properties of undoped single crystals of LiBaAlF6 (LBAF). The spectrum of the refraction index in the ultraviolet–visible range was recorded. The photoluminescence excitation spectroscopy was carried out for both the excitonic (4.3 eV) and fast vacuum ultraviolet (6.6 eV) emission bands of LBAF single crystals at 10 K. Modeling of the photoluminescence excitation spectra for excitonic emission was performed to characterize the low-energy tail of the host absorption of LBAF single crystals. The pulse cathodoluminescence spectroscopy method was used to characterize the fast vacuum ultraviolet (6.6 eV) emission band and proof its origination from the radiative core-valence transitions F− 2p  →→ Ba2+ 5p.