Photoluminescence of Tl4HgI6 single crystals

The temperature behavior of Tl4HgI6 photoluminescence spectra is presented. The emission spectra are studied in the temperature range between 4.5 and 300 K and in the spectral range 350–650 nm. Two main emission bands at ∼551 nm and ∼448 nm are observed corresponding to the emissions of HgI2 and Tll impurity centers. It is assumed that the low-temperature emission band at ∼520 nm corresponds to the recombination of the exciton. The luminescence peaks observed in emission spectra in the range between 350 and 410 nm correspond to the phonon repetitions. The excitation spectra of emission bands are measured at 4.5 K and compared with the electron density of states.