Investigating the origin of intense photoluminescence in Si capping layer on Ge_1−xSn_x nanodots by transmission electron microscopy Available to Purchase

The authors investigated the annealing effects on atomic structures and elemental compositions in a stacking structure, Si capping layer on Ge_1−xSn_x nanodots on Si substrate covered with ultrathin SiO₂ film, to clarify the origin of intense photoluminescence at ∼0.8 eV from the structure, using transmission electron microscopy. After the annealing, it was found that decay of Ge_1−xSn_x nanodots, formation of SiO_x precipitates embedded in Si-rich Si_1−xGe_x layer at the Si cap/Si substrate interface, formation of SnO₂ nanoparticles on the oxidized surface of the Si capping layer, and morphological change of dislocations in the Si capping layer occur. Reaction products that appear as a result of the movement of dislocations can be related to the origin of intense photoluminescence.