Three-Dimensional Lithography for Rutile TiO_2 Single Crystals using Swift Heavy Ions

摘要

We have developed a nano-micro structure fabrication method in rutile TiO_2 single crystal by use of swift heavy-ion irradiation. The area where ions heavier than Cl ion accelerated with MeV-order high energy were irradiated was well etched by hydrofluoric acid, by comparison etching was not observed in the pristine TiO_2 single crystal. Noticed that the irradiated area could be etched to a depth at which the electronic stopping power of the ion decayed to a value of 6.2keVm. We also found that the value of the electronic stopping power was increased, eventually decreased against depth in TiO_2 single crystal with, e.g. 84.5MeV Ca ion. Using such a beam, inside of TiO_2 single crystal was selectively etched with 20% hydrofluoric acid, while the top surface of TiO_2 single crystal subjected to irradiation was not etched. Roughness of the new surface created in the single crystal was within 7nm with the atomic forth microscopy measurement.