Growth of ZnO-Nanorod Grating on the Seed Grating Produced by Femtosecond Laser Pulses

Abstract

In this research, we successfully fabricated ZnO-nanorod grating by carrying out femtosecond-laser modification of the seed layer. First, a Ag-doped ZnO seed layer was deposited on a glass substrate by dc/rf magnetron co-sputtering, in which rf and dc power sources were utilized for the ZnO and the Ag targets, respectively. Next, a seed grating was produced on the seed layer by using the two-beam interference of femtosecond-laser pulses. Finally, a ZnO-nanorod grating was grown on the seed grating by chemical bath deposition in an aqueous solution of Zn(NO3)(2) and hexamethyltetramine. The scanning-electron-microscopy images indicate that the ZnO-nanorod grating can be regarded as a spatially periodic structure consisting of alternating bands of ZnO nanorods with relatively large and small diameters. The selected-area electron-diffraction patterns of the seed grating reveal that the formation of the ZnO-nanorod grating is attributable to the spatially selective modification of the seed layer produced by femtosecond-laser pulses.