Directing photophysics and structure in semiconductor nanowires with erbium and germanium

Recent efforts from our labs have focused on the fundamental properties of erbium incorporated into Ge nanowires (Ge NWs) and a diverse number of radial core/shell platforms containing these two elements. In this review we focus on two beneficial outcomes that can be exploited from such structures to even broader families of nanostructures: (a) the useful chemical and photophysical utility of providing wide bandgap oxide shells onto germanium nanowire cores containing rare earth ions such as erbium; (b) the unique combination of germanium and tin in an erbium doped oxide nanowire to engage in a spontaneous oxidation-reduction reaction that enhances the erbium near infrared photoluminescence (PL). A broad range of spectroscopic (PL, PL excitation) and structural (high resolution transmission electron microscopy, scanning electron microscopy, Raman spectroscopy, and energy dispersive X-ray analysis) tools are employed for this evaluation.