Fast intrinsic emission in Cs2CdI4Cs2CdI4 single crystal

The spectral-luminescent studies of the Cs2CdI4Cs2CdI4 single crystals are reported. The fast luminescence in the 3.6–2.0 eV energy range with decay time τ=4.6ns was revealed in the crystal under high-energy excitation (Eexc>8eV) at 9 K. This luminescence is supposed to be caused by the hole transitions between subbands of the split valence band. The energy-band picture for Cs2CdI4Cs2CdI4 crystals was calculated as a proof of the luminescence model.