Anomalous Enhancement of IR Emission in Zn_(1-x)Mn_xS Retrieved after Pressure-Induced Phase Transition

摘要

A new intense IR photoluminescence band peaking around 880 nm is generated in Zn_(1-x)Mn_xS (x=0.01 to 0.10) samples which are retrieved after the pressure-induced transformation from the zinc-blende to the rack-salt structure. The external photoluminescence quantum yield is two orders of magnitude larger as compared with the usual 2 eV emission band in virgin crystals.The photoluminescence excitation spectra have revealed that the excited ~4T_1 state of the Mn ion acts as the initial state of the electronic transition accompanied with large lattice distortions. Although such distorted Mn centers are metastable, as demonstrated by thermal treatments, the emission intensity does not decrease within months at room temperature.