RAMAN-SPECTROSCOPY AND THE PRESSURE EFFECT OF THE DILUTED MAGNETIC SEMICONDUCTORS ZN1-XMNXSE

The Raman spectroscopy of Zn1-xMnxSe thin films with Mn concentration x = 0.04, 0.19 and 0.32 and high pressure induced phase transition of Zn0.76Mn0.24Se crystal are investigated. The energy-dispersive x-ray d iffraction (EDXD) is used to study the pressure induced phase transiti on. It is found the zone-center optical phonons of Zn1-xMnxSe thin fil ms exhibit an intermediate mode behaviour. For Zn0.76Mn0.24Se crystal, three Raman modes: one TO mode at 197.2 cm(-1), one LO mode at 249.4 cm(-1), and a Mn local mode located at 222.5 cm(-1) are found at ambie nt pressure. The Mn local mode splits into two modes at 4.7 GPa while visible anomaly splittings of TO mode occur at 6.0 and 8.9 GPa. The se miconductor-metal phase transition of Zn0.76Mn0.24Se crystal is observ ed at 9.6GPa which is 4.8 GPa lower than that of ZnSe crystal. The red uction of the phase transition pressure is ascribed to the increasing of the volume factor of the impurity atom.