Depth-resolved cathodoluminescence of ion-implanted layers in zinc oxide

Single-crystal substrates of ZnO prepared from a large boule of hydrothermally grown material were implanted with ions of Li, Na, N, P, and Ne using energies in the range 30 keV–1 MeV and doses of 1×1011–1×1016 ions/cm2 using substrates maintained at either room temperature or 475 °C. These implanted layers were studied using depth-resolved cathodoluminescence. The spectra obtained agreed well with those expected based on a comparison of theoretical electron-hole pair profiles and computer-generated ion implantation profiles. The spectra of all samples implanted at 475 °C exhibited a peak near 6500 Å, and a series of previously unreported phonon-coupled peaks analogous to the well-known CdS ’’edge’’ emission was observed to some extent in all the implanted samples, independent of implant species. The luminescence could be quenched by annealing above 600 °C and is probably a result of the formation of damage centers.