Waveguide effect in ZnO crystal by He + ions implantation: Analysis of optical confinement from implant-induced lattice damage

Waveguide effect was observed in He+ implantation ZnO with different energies and doses. Computer code was used to simulate the process of ion implantation into ZnO crystal and the implantation-produced damage distribution is extracted according to RBS experimental result. The prism coupling and end-face coupling technique are used to investigate the waveguide properties. The reconstructed refractive index profile shows that the ordinary index decreases at the near surface region after He+ implantation under different conditions. The damage layer, which is governed by nuclear energy deposition of He+ ions, makes itself a reduced index barrier for guiding light. Ion-implantation, generally used for electrical isolation, may play a role for optical confinement in ZnO light emitting devices.