Synthesis of germanium oxide nanoparticles in low-pressure premixed flames.

Germanium oxide (GeOx) nanoparticles in the size range from 1 nm to 5 nm were synthesized in a low-pressure premixed H2/O2/Ar flat flame of 30 mbar. The premixed flame was doped with different amounts of tetramethyl germanium (Ge(CH3)4) ranging from 250 ppm to 2000 ppm. The influence of process parameters such as the amount of oxygen in the reaction gas, the condensation and reaction time, standoff, and precursor concentration with respect to growth of germanium oxide particles were investigated.