Raman scattering from irradiated nanocrystalline zinc oxide thin films: Perspective view on effects of energy loss, ion fluence, and ion flux

• Published in: Vacuum 2020-11, Vol.181, p.109598, Article 109598
• Main Authors: Gupta, Himanshi, Joshi, Kanchan, Gautam, Subodh K., Singh, R.G., Singh, Fouran
• Format: Article
• Language: English
• Subjects: Displacement per atom (dpa); Ion implantation; nc-ZnO thin films; Raman modes; Raman tensor
• ISSN: 0042-207X; 1879-2715
• DOI: 10.1016/j.vacuum.2020.109598

Raman scattering were used to study lattice damage in nanocrystalline zinc oxide (nc-ZnO) thin films implanted with 300 keV Ar and 1.2 MeV Xe ions at different ion fluences and ion fluxes. Raman spectra of all of the implanted samples show a broad Raman band at the lower Raman shift side along with A1 (LO) phonon mode. The A1 (LO) phonon modes get evolved with an increase in ion fluence with the reduction in the intensity of E2 (high) mode which is the characteristic mode of the wurtzite phase of ZnO. The implanted films show broadening and softening of A1 (LO) phonon mode upon an increase in ion fluences and observed to be more prominent in the case of 1.2 MeV Xe ions as compared to 300 keV Ar ions. The evolution of A1 (LO) phonon mode and broadening of Raman band assigned to the damage induced in the system upon ion-implantation and correlated well with the damage profile, while the peak broadening and softening could be assigned to the stress-induced into the films due to implantation. Thus, for a better understanding, the Raman tensor of first-order optical Raman modes in back-scattering geometry is also presented in the manuscript. •Lattice damage in nanocrystalline zinc oxide (nc-ZnO) thin films by 300 KeV Ar and 1.2 MeV Xe ions implantation.•Evolution of broad Raman band at the lower Raman shift side along with A1 (LO) phonon mode.•Peak shape of A1 (LO) phonon mode found to be sensitive to damage or defects in the ZnO.•Broadening and softening of A1 (LO) phonon mode is more prominent in the case of 1.2 MeV Xe ions as compared to 300 KeV Ar ions.•The evolution of A1 (LO) phonon mode and broadening of Raman band assigned to the damage induced in the system upon ion-implantation and correlated well with the damage profile.