Controlled growth of GaN nanowires by focused ion beam Pt-catalyst patterning

One-dimensional GaN nanostructures are promising materials for nano-device applications. Control of nucleation density and position is a critical issue to fabricate such devices using GaN nanowires (NWs). However, only a few studies of controlled GaN growth are reported so far.$^{2)}$ An attractive approach is to use the spatial selectivity and resolution of focused ion beam (FIB) to deposit platinum (Pt) catalyst seeds for GaN NW growth at desired positions. In the present work, we demonstrate the successful patterned growth of GaN NWs on SiO$_{2}$/Si substrates or SiN$_{x}$ TEM grids using FIB Pt-patterning. The thermal reaction of Ga$_{2}$O$_{3}$ and NH$_{3}$ on the substrates at $\sim$920$^{\circ}$C was used for GaN NW growth.$^{3)}$ Grown NWs were analyzed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). We conclude that Pt acts as a catalyst for GaN NW growth, and that FIB provides the control over density and position of GaN NW growth, which ultimately can be utilized for nano-device fabrication. This work is supported by the NSF NIRT Program under Grant No. DMR-0304178 1) Y. Huang, X. Duan, Y. Cui, and C. M. Lieber, Nano Lett., \textbf{2(2)}, 2002, 101-104. 2) J. Li, C. Lu, B. Maynor, S. Huang, and J. Liu, Chem. Mater., \textbf{16}, 2004, 1633-1636. 3) C. Y. Nam, D. T. Tham and J. E. Fischer, Appl. Phys. Lett. (in press, December 6, 2004).