Development of low temperature technology for the growth of wide band gap semiconductor nanowires

Abstract

In2Ge2O7, Ge3N4, In2O3 and germanium nanowires were synthesized by the developed hydrazine (N2H4)-based technology. Annealing of germanium or Ge+In sources in the vapor of N2H4+3 mol.% H2O caused the formation of volatile GeO and In2O molecules in the hot zone. These molecules were transferred to the Si substrate, which was placed in the could zone of a reactor. After interacting with hydrazine decomposition products (NH3, NH2, NH, H2, H) and water, Ge3N4 nanowires and nanobelts were produced on the Ge source in the temperature range of 500–520 oC. The growth temperature of Ge3N4 nanowires in hydrazine vapor was by 350 oC lower than the temperature reported in the literature. Using In+Ge source the tapered In2O3 nanowires were formed on the Si substrate at 400 oC. At 420–440 oC the mixture of In2O3 and Ge nanowires were synthesized, while at 450 oC In2Ge2O7 nanowires were produced, with InN nanocrystals growing on their stems. The possible chemical reactions for the synthesis of these nanostructures were evaluated. The growth temperatures of both, In2Ge2O7 and InN nanostructures were by 50–150 oC lower than that, reported in the literature. The results of this work clearly demonstrate the ability of hydrazine vapor to reduce the growth temperature of nitride and oxide nanomaterials.