Pure, single crystal Ge nanodots formed using a sandwich structure via pulsed UV excimer laser annealing

摘要: In this paper, a sandwich structure comprising SiO2 capping layer, amorphous Germanium (a-Ge) nanodots (NDs), and pit-patterned Silicon (Si) substrate is developed, which then annealed by utilizing pulsed ultraviolet excimer laser in order to fabricate an array of pure, single crystal Ge NDs at room temperature. A wide bandgap layer used as transparent thermally isolated prevent thermal loss Si–Ge intermixing. The two-dimensional Si designed confine the absorbed energy, reduce melting point, block surface migration Ge. After optimizing radiation parameters such that energy density 200 mJ cm−2, annealing period 10 s, number shots 10, have both regular arrangement uniform size distribution are obtained pits substrates. Raman spectrum shows highly symmetric transversal optical peak with full width half maximum 4.2 cm−1 300.7 cm−1, close original wafer. addition, high-resolution transmission electron microscopy image for corresponding selected area diffraction pattern clear crystalline without any impurities.