The origin of additional modes in Raman spectra of ZnO:Sb films

Abstract

Systematic Raman spectroscopic study was conducted on the wurtzite (002) Sb-doped ZnO films grown by pulsed laser deposition with different Sb doping levels and annealed at different temperatures, with the undoped, Cu-doped and Ga-doped ZnO films for comparison. Three additional Raman modes 235 cm−1, 510 cm−1 and 534 cm−1 were observed only in the Sb-doped ZnO samples but not in the other controls. The vibration mode 235 cm−1was associated with the SbZn-related shallow donor, which was the origin of the n+-conductivity. The 510 cm−1 vibrational mode has been associated with HO in previous literature. However in the current study, the correlation between its intensity and the H abundance was not observed. The 534 cm−1 Raman mode was associated with a Sb-related defect. The variation of the intensities of the Raman modes 235 cm−1 and 510 cm−1 upon annealing and change of Sb composition were discussed.