Luminescence in semiconductor-ferroelectric Sn2P2Se6 crystals

Luminescence spectra of Sn2P2Se6 crystals are investigated in the temperature range of 8 – 67K. On the basis of analysis of the obtained data we show that the broad emission band with the maximum at about 600 nm (for the temperature T=8.6 K) can be assigned to the band-to-band electron-hole recombination, whereas the broad emission bands peaked near 785 nm (T=8.6 K) and 1025 nm (T=44K) can be assigned to electron-hole recombination from the levels of defects, which are localized within the bandgap. Based on the referenced data, possible types of the recombination defect centres in Sn2P2Se6 crystals are discussed.