MCD investigation on Mn doped CdSe Quantum Ribbons

We have successfully incorporated manganese ions into 1.4 nm thick CdSe nanoribbons, thus generating 1-dimensionally quantum confined diluted magnetic semiconductor nanostructures. A series of CdSe:Mn nanoribbons with Mn concentration ranging from 0.7 to 6.4\% have been investigated using magnetic circular dichroism (MCD) spectroscopy in order to study spin effects in these CdSe:Mn quantum ribbons. In all samples, a strong MCD signal was found at the energy about 2.9 eV (435 nm), which corresponds to the 1S$_h$-1S$_e$ transition, indicating a strong enhancement of the exciton Zeeman splitting due to the $sp-d$ exchange interaction between the CdSe nanoribbon host and the incorporated Mn$^{2+}$ ions. In addition, the magnetic field dependence of the MCD signal obeys a Brillouin function. Finally, we found that the Zeeman splitting energy $\Delta$E calculated from the MCD signal increases with the Mn concentration, which clearly demonstrates that Mn$^{2+}$ ions are indeed present in the CdSe nanoribbons.