Self-assembly of well-ordered and highly uniform nanoripples induced by focused ion beam

Well-ordered and highly uniform nanoripple structures on the surface of single crystal LaAlO3 (1 0 0), SrTiO3 (1 0 0) and Al2O3 (0 0 0 1) were formed via self-assembly (not by beam writing) by focused ion-beam bombardment. The morphology and topography of nanoripple structures were characterized using in-situ focused ion-beam/scanning electron microscope, as well as ex-situ atomic force microscopy. Under off-normal bombardment without sample rotation, the characteristic wavelength of nanoripples varying from 248 to 395 nm on the LaAlO3 (1 0 0) surface can be obtained by changing ion fluence and incident angle. When all sputtering parameters except the ion fluence are constant, the wavelength of nanoripples is increased with the enhanced ion fluence. These results demonstrate the potential application of using ion sputtering method for fabricating the well-ordered and highly uniform nanoripples which can be used in nanodevices.