Regular Arrays of (Zn,Mn)S Quantum Wires with Well-Defined Diameters in the Nanometer Range

Abstract

Zn1−x Mn x S, with x varying between 0.01 and 0.30, were formed inside the ordered pore systems of different mesoporous SiO2 matrices. Because of the highly ordered structure of the hosts, regular arrays of Zn1−x Mn x S quantum wires with lateral dimensions of 3 and 5.5 nm, respectively, separated by 2-nm SiO2 barriers were obtained. The wires were characterized using photoluminescence (PL) and PL excitation (PLE) spectroscopy at liquid Helium temperatures. The PL of the wires is dominated by the 4T1 → 6A1 internal transition of the Mn2+(3d5) ions. The corresponding PLE spectra show higher internal Mn transitions as well as the band to band transition. The energies of the internal Mn transitions are typical for Mn2+ on a cation site of (II,Mn)VI semiconductors. Because of the comparable bandgaps of the SiO2 and the Zn1−x MnxS as well as the small exciton Bohr radius in (Zn,Mn)S quantum confinement effects in the wires are less than about 150 meV.