The Raman Spectra Study Of GZO Crystal And Ceramics

GZO crystals and ceramics with different concentration of Ga doping were measured by Raman spectroscopy and X-ray diffraction. It could be confirmed the optimum doping component of Ga and figured out the doping form of Ga3+ in the lattice by the lattice variation of the samples.The results of X-ray diffraction showed that GZO crystals and ceramics were still maintained a hexagonal wurtzite structure after Ga doped. And it also appeared significant changes in the Raman spectra. Firstly, the E2?low? and E2?high? mode who were the characteristic bands of ZnO were found at 98 cm^-1 and 437 cm^-1, respectively. And in the spectra of GZO crystal, the band located around 378cm^-1 who was assigned to A1?TO? mode was not obvious in pure ZnO, it usually associated with the intrinsic defects of ZnO, and was forbidden in the back scattering configuration, but now it can be observed significantly when doping with Ga, so it was probably caused by Ga who substituted Zn-site and induced the intrinsic defects emerged. There was aslo a new band appeared around 488 cm^-1, it was confirmed to the vibration of the M point in the Brillouin zone from the phonon dispersion curves and the polarized Raman scattering. For GZO ceramics, there appeared new bands at the 584 cm^-1 and was assigned to E1?LO? mode by resonant Raman scattering.The bands around 631 cm^-1 and 1148 cm^-1 both appeared in the Raman spectra of GZO crystals and ceramics. The band at 1148 cm^-1 undergone some changes with the increasing of Ga doping concentration, and it was assigned to the overtone of E1?LO? by resonant Raman scattering. As for 631 cm^-1, we assigned the local vibration mode caused by Ga-O bond vibration, which was the substitution of Ga for Zn-site with O?LVMGa-O?.