Growth and characterization of Si1−xGetx QDs on Si/Si0.8Ge0.2 layer

Si 1− x Ge t x QDs structures were grown onto Si/Si 0.8 Ge 0.2 layer using RPCVD system. Ge composition in Si 1− x Ge t x QDs was determined as about 30% and 40%. Three peaks are observed in Raman spectrum, which are located at about 520, 410, and 295 cm −1 , corresponding to the vibration of Si-Si, Si-Ge, and Ge-Ge phonons, respectively, and the Si 1− x Ge t x QDs related peak was located at 490 cm −1 . The PL spectrum that originates from the radiative recombinations came from the Si substrate, the Si 0.8 Ge 0.2 layer and Si 1− x Ge t x QDs. For Si 1− x Ge t x QDs, the transition peaks related to the QDs region observed in the photocurrent spectrum were preliminarily assigned to electron-heavy hole (e-hh) and electron-light hole (e-lh) fundamental excitonic transitions.