Silver catalyzed growth of InxGa1−xAs nanowires on Si(001) by metal–organic chemical vapor deposition
We report the growth of InxGa1−xAs nanowires on Si(100) substrates by the metal–organic chemical vapor deposition technique in a one-step process using silver nanoparticles as catalysts. Nanowires were found to grow below the eutectic temperature of Ag–Si over a wide range of temperature. The morphology and mode of nanowire growth were found to change with growth temperature. The images obtained from field-emission scanning electron microscopy reveal that growth at 600 °C promotes multi-prong nanowires, while nanowires grown at a lower temperature are single-prong. The effect of temperature on the growth of nanowires was explained with the help of a model developed on the basis of classical nucleation theory. X-ray photoelectron spectroscopic measurements validate the growth of InxGa1−xAs nanowires on Si. A pure zinc blende phase, free from stacking defects, is observed from high-resolution transmission electron microscopy images and the associated indexed selected area electron diffraction patterns. The optical bandgap energy of the nanowire ensemble was calculated by diffused reflectance spectroscopy. Compositional mapping using energy dispersive X-ray spectroscopy shows uniform distribution of three constituent elements along the length of the nanowires. Our study gives new insights into the particle-assisted growth mechanism of III–V compound nanowires and promotes the use of Ag nanoparticles as catalysts as a better option over gold nanoparticles which will eventually help in integrating III–V nanostructures with existing silicon microelectronics to pave the way for photonic devices on silicon.