Synthesis of Low-Melting Metal Oxide and Sulfide Nanowires and Nanobelts

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 b-Ga2O3, b-In2O3, SnO2, a-Ga2S3, and b-In2S3 were synthesized using direct reactions between respective molten metal pools and the gases such as oxygen/hydrogen mixture for oxides and H2S for sulfides. In the case of b-Ga2O3 and SnO2, 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 b-In2O3. Furthermore, we present evidence for a-Ga2S3 nanowires, which to our knowledge is being reported for the first time in the literature. Our studies with the sulfide nanowires suggest that H2S 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 b-Ga2O3 and SnO2.