Non-polar ZnO facet implanted with Au ions and subsequently modified using energetic O ion irradiation

Modification of structure and surface morphology in various ZnO facets via low fluence gold swift heavy ion irradiation

“…However, when the crystallographic orientations are compared, the normalised yield in the m ‐plane grows more progressively than in the c ‐plane, whereas in fact, no changes are visible in the a ‐plane. The differences in the structure modification in various ZnO orientations have been studied in our previous experiments, but for much lower ion irradiation energies 17,18 and in detail mainly for the c ‐plane also in previous studies, 30,32 using medium‐energy ion implantation as a doping technique and with several orders of magnitude higher ion fluences. It is clear that the situation in this experiment is different, because single‐ion impacts with high electronic stopping are expected.…”

“…In the Raman spectrum, it is possible to identify distinct phonons that can be ascribed to each orientation. The optical phonons at the Γ point of the Brillouin zone have the following irreducible representation: Γ opt = 1 A 1 + 2 B 1 + 1 E 1 + 2 E 2 , where A 1 and E 1 modes are polar and split into transverse (TO) and longitudinal optical (LO) phonons 18 . The Raman spectra of the as‐irradiated and pristine samples are shown in Figure 3A–C for the c ‐, a ‐ and m ‐plane ZnO, respectively.…”

“…Hydrothermally grown ZnO single-crystal wafers (10 × 10 × 0.3 mm 3 ) with ( 0001), (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) and (10-10) crystallographic orientations were purchased from Crystal GmbH, Germany. The samples used with their surfaces along the crystallographic planes (0001), (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) and are labelled as c-plane, a-plane and m-plane, respectively. All ZnO facets were implanted with Au + ions with the energy of 30 MeV and the fluence gradually increasing from 5 × 10 9 to 5 × 10 11 cm −2 using a Tandetron accelerator.…”

“…16 We have studied the defect accumulation and type in various ZnO facets; the study has revealed interesting differences appeared, and it has shown that optical properties can be tuned in various facets in a distinct way. 17,18 During the growth of various ZnO nanostructures (nanobelts, nanoribbons, etc. ), it was found that the growth rate along the <0001> axis is different from those along the <11-20> and <10-10> axes.…”

“…), it was found that the growth rate along the <0001> axis is different from those along the <11-20> and <10-10> axes. The development of (0001) polar surfaces during the ZnO nanostructure growth is not energetically favourable owing to their higher surface energy than in the case of the and (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) non-polar planes 19 ; the nucleation of the planar defects in these planes can thus be enhanced. 20 In such facets, it is possible to expect prominent growth of defects and/or nanostructures under the ion-beam irradiation, which can lead to the appearance of distinct nanostructures in various ZnO facets.…”