Growth Optimization for Self-Catalyzed GaAs-based Nanowires on Metal-Induced Crystallized Amorphous Substrate

The growth of monocrystalline semiconductor nanowires on arbitrary substrates via the metal-induced crystallization (MIC) process extends the possible combinations of substrates and epitaxial active materials. However, it is still difficult to accomplish high-density vertical nanowire growth on the MIC polycrystalline Si(111) substrate. Here, the authors report on the growth of self-catalyzed GaAs nanowires by molecular beam epitaxy on MIC polycrystalline Si(111) substrates with different surface oxide conditions. Forming the surface oxide by annealing the freshly hydrofluoric acid-etched MIC polycrystalline Si(111) substrate in an ambient atmosphere is found to be a key step to grow high-density GaAs nanowires. Moreover, the addition of Sb during nanowire growth improves the density of vertical nanowires. Photoluminescence measurements reveal a high optical quality of the GaAs nanowires, indicating that the nanowires grown on MIC polycrystalline Si(111) substrate may be used as building blocks for semiconductor nanowire optoelectronic devices on arbitrary substrates.