Size and shape control of GaAs nanowires grown by metalorganic vapor phase epitaxy using tertiarybutylarsine

Au-catalyzed self-assembly of GaAs nanowires on (111)B GaAs by metalorganic vapor phase epitaxy is reported between 375 and 500 degrees C, using tertiarybutylarsine and trimethylgallium in H-2. The nanowires are [111]B aligned and kink-free. Below 425 degrees C the nanowires have narrow base diameter distributions, closely matching the size (similar to 60 nm) of the Au nanoparticles at their tip (no tapering). Above 425 degrees C the nanowires show a hexagonal-based pyramidal shape with base edges normal to the < 211 > in-plane substrate directions and base diameters which increase exponentially with temperature, indicating a kinetics limited growth along the nanowire sidewalls. Activation energies in the range of similar to 20-23 kcal/mol were estimated for growth along both the sidewalls and the B direction.