Synthesis of low-melting metal oxide and sulfide nanowires and nanobelts

Abstract

The bulk nucleation and basal growth of semiconducting nanowires from molten Ga pools has been demonstrated earlier using oxygen/hydrogen plasma over molten Ga pools. Herein, we extend the above concept for bulk synthesis of oxide and sulfide nanowires of low-melting metal melts such as Sn and In. Specifically, nanowires of β-Ga_2O_3, β-In_2O_3, SnO_2, α-Ga_2S_3, and β-In_2S_3 were synthesized using direct reactions between respective molten metal pools and the gases such as oxygen/hydrogen mixture for oxides and H_2S for sulfides. In the case of β-Ga_2O_3 and SnO_2, a change in the morphology from nanowires to nanobelts was observed with an increase in the synthesis temperature. No such behavior was observed in the case of β-In_2O_3. Furthermore, we present evidence for α-Ga_2S_3 nanowires, which to our knowledge is being reported for the first time in the literature. Our studies with the sulfide nanowires suggest that H_2S reacts directly at the molten metal surface to form gallium sulfide. Finally, we discuss the role of chamber pressure and hydrogen on the size distribution of nanostructured β-Ga_2O_3 and SnO_2.