Comparison of the optical properties of as-grown ensembles and single ZnO nanowires

Surface related and intrinsic exciton recombination dynamics in ZnO nanoparticles synthesized by a sol-gel method

“…19 The asymmetric SX also dominates the near-band-edge PL in ZnO nanorods with diameters d < 40 nm. 20 In our case, the surface to volume ratio of the NPs is much larger than for nanorods, and accordingly the surface effect should be obvious in NPs. Theoretical calculations have demonstrated that excitons can be bound to ionized impurities located at the surfaces of quantum dots (QDs).…”

Microscopic origins of the surface exciton photoluminescence peak in ZnO nanostructures

“…26,27 Briefly, ZnO nanostructures were grown on Au-catalysed a-plane (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) sapphire substrates and n-type (resistivity 2.5-8 ohm cm) and p-type (resistivity 5-9 ohm cm) Si substrates using vapour phase transport (VPT). A 5 nm Au layer was evaporated onto 5 mm diameter circular or 9 mm 2 square continuous areas on the ultrasonically cleaned substrates using a thermal evaporator.…”

Microscopic origins of the surface exciton photoluminescence in ZnO nanostructures

“…There is evidence in support of this in the literature, including reports of low temperature PL from ZnO nanostructures with varying aspect ratios, which show no consistent correlation from one report to another between the SX peak relative intensity and the nanostructure aspect ratio (as well as variations with morphology variations seen within individual reports) see e.g. ref 15, 22-24.…”

“…3,2,6,10,15 However, a number of reports of low temperature PL from ZnO nanostructures with varying aspect ratios show no consistent correlation from one report to another [22][23][24] and within the same report 2,15 between the SX peak relative intensity and the nanostructure aspect ratio. Based on the entirety of these reported data we question whether the SX peak's relative intensity is solely or mainly determined only by the nanostructure surface-to-volume ratio.…”

“…25,26 Briefly, ZnO nanostructures were grown on Au-catalysed a-plane (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) sapphire substrates and Si substrates using vapour phase transport (VPT). A 5 nm Au layer was evaporated onto 5 mm diameter circular or 9 mm 2 square continuous areas on the ultrasonically cleaned substrates using a thermal evaporator.…”