Generation of Charged Nanoparticles during the Synthesis of GaN Nanostructures by Atmospheric-Pressure Chemical Vapor Deposition

The possibility that GaN charged nanoparticles might be generated during the synthesis of GaN nanostructures was examined in an atmospheric-pressure chemical vapor deposition (CVD) process using a differential mobility analyzer combined with a Faraday cup electrometer. Both positively and negatively charged nanoparticles in the size range of 10-100 nm were generated in the reactor of the CVD process using Ga2O3 precursor and NH3 gas. With decreasing flow rate of NH3 from 400 to 0 standard cubic centimeter per min (sccm) and decreasing reactor temperature from 1100 degrees C to 500 degrees C, the size and the number concentration of charged nanoparticles decreased. As the size and the number density decreased, the size of deposited GaN hexagonal crystals decreased and eventually GaN nanowires began to grow without catalysts.