The aggregation of Fe and their d-d radiative transitions in ZnSe:Fe nanobelts by CVD growth.

Transition metal (TM) doped II-VI semiconductors have attracted great attention due to their luminescence and diluted magnetism. In this study, the Fe-doped ZnSe nanobelts (NBs) were grown by a facile CVD method. The surface morphology observed SEM is smooth and clean and the elemental composition measured EDS confirms that the Fe ions were incorporated into ZnSe NBs successfully. The micro-Raman scattering spectra demonstrate that the as-prepared NBs have the zinc blende structure. Furthermore, the Raman spectra of the Fe-doped NBs were compared with those of pure and Fe-doped reference samples. The former with a higher signal-to-noise ratio, an enhanced 2LO mode, a stronger LO mode redshift and a larger intensity ratio of LO/TO mode as well as the lower acoustic phonon modes confirms the better crystallization and the stronger electron-phonon coupling on Fe-incorporation. The emission of single Fe ion, assigned to the T → A transition, was observed at about 570 nm. Moreover, increasing the doping concentration of Fe ions caused the formation of different Fe-Fe coupled pairs in the lattice, which emitted light at about 530-555 nm for an antiferromagnetic-coupled pair, possibly due to the stacking faults and at about 620-670 nm for a ferromagnetic-coupled pair.