Temperature dependence of surface plasmon mediated near band-edge emission from Ag/ZnO nanorods

Abstract

Surface plasmon (SP) mediated near band-edge emission in Ag/ZnO nanorods has been systematically studied by using a temperature-dependent photoluminescence spectra technique. It was found that the mediation mainly concerns SP couplings with two emissions, one from neutral donor-bound exciton D 0 X recombination and another from the radiative transition of free electron to neutral acceptor (e, A 0). The first coupling process is demonstrated to prevail in the temperature range from 300 to 150 K, while the second is dominant below 150 K. The competition mechanism and the role of exciton and carrier delocalizations in the coupling processes have been explored in the unique Ag/ZnO nanostructures.

Evidence for coupling between exciton emissions and surface plasmon in Ni-coated ZnO nanowires

“…We note that the Ni-induced surface recombination seems to mainly occur via non-radiative processes to account for the observed quenching of the SX emission. The suggested scenario is also consistent with the results of the TR PL [26]. Remarkably, the Raman intensity is significantly enhanced in the Ni-coated ZnO NWs, e.g.…”

“…Figure 7 shows Raman scattering spectra measured from the investigated ZnO NWs before and after Ni coating. For all samples, the spectra contain a number of peaks spaced by about 572 cm −1 due to the first-and multiple-order Raman scattering involving longitudinal optical (LO) phonons, as well documented in the literature [25]. Remarkably, the Raman intensity is significantly enhanced in the Ni-coated ZnO NWs, e.g.…”

“…The oscillator strength of the BX transitions is significantly lower than that of the FX [24], which should lead to their weaker coupling with the SPs. Moreover, localization of the BX may further decrease the probability of their scattering into the SPs as compared with the FXs, which are highly mobile [25]. As a result, the detrimental effect of the enhanced surface recombination becomes predominant, leading to the observed decrease in the PL intensity in the Ni-coated structures.…”

Optical study of a two-level defect complex in gallium doped ZnO

“…With growing temperature, a continuous redshift of 70-90 meV from the near band edge emission is observed. In other words, the PL emission is dominated by ionized donor bonded emission at low temperature and by DAP emission at room temperature, respectively, similar to previous reports [23]. These near band edge emission features of ZnO:Ga have been intensively studied; and it is not the main subject to be discussed in this paper.…”