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

Abstract

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.