Local vibrational modes and Fano interaction in p-type ZnO:Sb system

Local vibrational modes (LVMs) and asymmetric phonon lineshapes are investigated in ZnO : Sb system. Two LVMs at 186 and 235 cm(-1) originating due to the change in reduced mass and reduction of localized interatomic force constant have been identified. Upon Sb-doping, the E-1(LO) mode of ZnO was found to shift towards the lower frequency side and broaden asymmetrically. These results are analysed within the framework of the Fano interaction in p-type ZnO. Temperature dependence of the E-1(LO) mode frequency and line width shows the conventional anharmonic behaviour in ZnO; whereas, it deviates in ZnO : Sb system. In addition, the carrier-phonon coupling strength was found to reduce at higher temperature.