The large-scale assembly of NWs with controlled orientation on surfaces remains one challenge toward their integration into practical devices. We report the VLS growth of perfectly aligned, millimeter-long, horizontal NWs of GaN [1], ZnO [2], ZnSe [3], ZnTe [4], CdSe [5] and other materials, with controlled crystallographic orientations on different planes of sapphire [1-5], SiC [6], quartz [7], and spinel [8]. The growth directions and crystallographic orientation of the NWs are controlled by their epitaxial relationship with the substrate, as well as by a graphoepitaxial effect that guides their growth along surface steps and grooves. As a proof of concept for future applications, we demonstrate the massively parallel “self-integration” of NWs into circuits via guided growth [9].
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5. ACS Nano, under review (2014).
6. Nano Lett., 13, 5491 (2013).
7. ACS Nano 8, 2838 (2014).
8. J. Phys. Chem C 118, 19158 (2014).
9. PNAS, 110, 15195 (2013).
