Figure 4 Raman spectra. (a) Pure ZnSe, (b) ZnSeMn, (c) , and (d) nanobelt, respectively. We studied further the luminescence properties of the as-synthesized Mn-ZnSe nanobelts by commercial SNOM. The insets of Figure 5a are bright-field optical and dark-field emission BYL719 price images of a single representative pure ZnSe nanobelt under the excitation of He-Cd laser (325 nm). The emission

is strong at the excitation spot. Figure 5a is the corresponding far-field PL spectrum. The band at 458 nm comes from the near-band edge emission of ZnSe, while the broad click here emission band at lower energy between 575 and 675 nm is attributed to the trapped-state emission [16]. Trapped-state and dangling bond, such as Zn vacancy and interstitial state,

are easy to form in nanostructures due to the reducing size. Therefore, the trapped-state emission is usually observed even in pure nanostructures [22]. The insets of Figure 5b are the bright-field optical and dark-field emission images of a single ZnSeMn nanobelt. Figure 5b is a corresponding far-field PL spectrum. We can observe a near-band edge emission of ZnSe with low intensity located at 461 nm and the trapped-state emission at 625 nm. There is another strong emission band at 545 nm, which can be explained by the dislocation, Quisinostat nmr stacking faults, and nonstoichiometric defects, as reported in reference [23–25]. We cannot observe the Mn ion emission (such as 4 T 1 → 6 A 1 transition emission at 585 nm) Adenosine which demonstrates that the Mn concentration is too low or there is no Mn doping into the ZnSeMn nanobelt. The insets of Figure 5c are the bright-field optical and dark-field emission images of nanobelt. Figure 5c is the corresponding far-field PL spectrum. Except for the weak near-bandgap emission and defect state emissions at 460 and 536 nm, there are two strong

emission bands at 584 and 650 nm. The 584-nm band corresponds to d-d (4 T 1 → 6 A 1) transition emission of tetrahedral coordinated Mn2+ states [26]. The 650-nm band is from the Mn-Mn emission centers, which is similar with the phenomenon of the Mn dimers [27, 28]. The Mn-Mn emission only occurs when the Mn dopant concentration is high enough [29]. There is another weak emission band at 694 nm, which is believed to originate from the Mn2+ ions at the distorted tetrahedral sites or the octahedral sites, due to the high Mn content [30, 31]. Manganese ions on such lattice sites show a different crystal-field splitting between the states of 3d orbitals, and then a red-shifted emission band is observed [32]. The appearance of the Mn2+ emission demonstrates the efficient doping of Mn2+ ion into the ZnSe crystal. We further carried out PL mapping of each individual emission band to explore the distribution of Mn2+ ions (Figure 5e). We can see that the distribution of near-band edge emission and Mn2+ ion emission is homogeneous in the whole nanobelt (see in Figure 5c).