Trapping High-Pressure Nanophase of Ge upon Laser Ablation in Liquid

The high-pressure nanophase, that is, the metastable tetragonal structure, of germanium is trapped by a facile technique named electrical-field assisted pulsed laser ablation in liquid at ambient pressure and temperature. On the basis of X-ray diffraction, transmission electron microscopy, and Raman scattering analyses, the trapped Ge nanophase is identified to be the tetragonal structure rather than the diamond structure of bulk germanium. First-principles calculations are used to clarify the physical and chemical mechanisms of the tetragonal Ge formation upon laser ablation in liquid.