Combined Super-STEM imaging, EEL and PL spectroscopy of un-doped and Er doped SRSO on Si

We present a combined analysis of Scanning Transmission Electron Microscopy (STEM) imaging and Electron Energy Loss spectroscopy (EELs) of silicon-rich-silicon-oxide (SRSO) thin film on silicon, grown by Plasma Enhanced Chemical Vapour Deposition (PECVD). For un-doped samples, strong room temperature luminescence at ~1.6eV (780nm) is observed, which we ascribe, by way of plasmon intensity mapping and ‘chemical fingerprinting’ to phase segregated, highly crystalline, silicon-rich nano-clusters embedded in an amorphous-silicon dioxide (${\mbi a}$-SiO2) matrix. For samples doped with increasing concentrations of Er, a quenching of the 1.6eV line, concurrent with the emergence of a second emission with increasing intensity at ~0.8eV (1535nm) is observed. This is attributed to a rapid and efficient, indirect nano-crystal mediated excitation of the Er.