Nanosecond laser induce size-controllable SiGe islands with high Ge composition, large aspect ratio and defect-free characteristics

In the present work, laser-induced directed dewetting (LIDD) of amorphous germanium thin films generates single crystalline SiGe islands on Si substrate. Furthermore, SiGe islands with a high aspect ratio of 1.06 are prepared by pulse laser irradiation. Variation of the nanosecond heating laser's pulse fluence enables modulation of the nanoscale island size, and the diameter of islands can be selected in the range of 40 nm-150 nm.