Controllable fabrication and cathodoluminescence performance of high-index facets GeO2 micro- and nanocubes and spindles upon electrical-field-assisted laser ablation in liquid

We have developed a unique technique, the facile electrical-field-assisted laser ablation in liquid (EFLAL) without any catalyst or organic additives, to controllably fabricate the mass production of GCO(2) micro- and nanoparticles with various shapes. By adjusting the applied electrical field, we synthesized the high-index facets GeO2 micro- and nanocubes and spindles, and propose the growth mechanisms of nanostructures upon EFLAL. On the basis of the cathodoluminescence measurements of dispersive GeO2 nanoparticles, we observed a shape-dependent red-shift of emission wavelength when the shape of GeO2 nanostructures transforms into spindle from cube, and then we established the physical model to address the anomalous red-shift of emission wavelength. Accordingly, we expecte EFLAL to be a general route to synthesize the micro- and nanostructures with metastable structures or metastable shapes.