Ge oxidation in the remaining cores of Si _1-xGe _x nanowires after prolonged oxidation

For this investigation of the Ge behavior of condensed Si _1-yGe _y (y > x) cores during the oxidation of Si _1-xGe _x nanowires, Si _1-xGe _x nanowires were grown in a tube furnace by the vapor-liquid-solid method and thermally oxidized. The test results were characterized using several techniques of transmission electron microscopy. The two types of Ge condensation are related to the diameter and Ge content of the nanowires. The consumption of Si atoms in prolonged oxidation caused the condensed SiGe cores to become Ge-only cores; and the continuous oxidation resulted in the oxidation of the Ge cores. The oxidation of Ge atoms was confirmed by scanning transmission electron microscopy.