Ge incorporation in gallium oxide nanostructures grown by thermal treatment.

Effective doping of semiconductor oxide nanostructures is needed to control n-type conductivity; however, out-diffusion of impurities in high quality crystals is still a bottleneck in nanotechnology. Here, germanium-doped gallium oxide (β-Ga2O3) nanowires have been grown by a thermal evaporation method. Two temperatures, close to Ge melting point, were chosen for the dynamic annealing of metallic gallium and germanium powders. At 840 °C, Ga2O3 nanowires and nanobelts grow along the b or c direction, leaving gallium germanate particles at the tip in both cases. Wider structures were produced at 940 °C, decorated with a Ge nanocrystal at the end. Transmission electron microscopy has been used to establish the vapor–liquid–solid-like growth process for the formation of these structures. The influence of Ge incorporation in the nanostructures has been assessed by cathodoluminescence and micro-Raman spectroscopy. The presence of Ge in β-Ga2O3 nanostructures is essential for electronic and optoelectronic applications since Ge is potentially the most effective n-type dopant for β-Ga2O3. [ABSTRACT FROM AUTHOR]