Raman Submicron Spatial Mapping of Individual Mn-doped ZnO Nanorods

Abstract

ZnO nanorods (NRs) arrays doped with a large concentration of Mn synthesized by aqueous chemical growth and were characterized by SEM, photoluminescence, Raman scattering, magnetic force microscopy (MFM). By comparison of spectra taken on pure and Mn-doped ZnO NRs, a few new Raman impurity-related phonon modes, resulting from the presence of Mn in the investigated samples. We also present a vibrational and magnetic characterization of individual lying nanorods using Raman and MFM imaging. Confocal scanning micro-Raman mapping of the spatial distribution of intensity and frequency of phonon modes in single Mn-doped ZnO NRs nanorods is presented and analyzed for the first time. Mn-related local vibrational modes are also registered in Raman spectra of the single nanorod, confirming the incorporation of Mn into the ZnO host matrix. At higher Mn concentration the structural transformation toward the spinel phase ZnMn2O4 and Mn3O4 is observed mainly in 2D bottom layers. MFM images of Mn-doped ZnO NR arrays and single nanorod were studied in nanoscale at room temperature and demonstrate magnetic behavior. The circular domain magnetic pattern on top of single nanorod originated to superposition of some separate domains inside rod. This demonstrates that long-range ferromagnetic order is present at room temperature. Aligned Mn-doped ZnO NRs demonstrates that long-range ferromagnetic order and may be applied to future spintronic applications.Electronic supplementary materialThe online version of this article (doi:10.1186/s11671-017-2127-4) contains supplementary material, which is available to authorized users.

Structure and properties of Mn3O4 thin films grown on single crystal substrates by chemical vapor deposition

“…The reversing of MFM contrast from bright to dark regions corresponds to tip-surface interaction changing from repulsion to attraction, i.e. magnetic moments directed up and down, respectively [33].…”

Structural, optical, thermoelectrical, and magnetic study of Zn1‐xCoxO (0 ≤ x ≤ 0.10) nanocrystals

“…Thermoelectric properties can be recovered by reducing thermal conductivity (κ), and increasing electrical conductivity (σ), and Seebeck coefficient ( S ). Experimental and theoretical studies suggest that substitution ZnO with transitional metal elements (M‐ZnO) such as Mn, Ce, Co, Ni, and Al can improve optical, electrical, and thermoelectric properties . Cobalt has received much recognition as a candidate material because the ionic radius of Co 2+ is close to that of Zn 2+ (a Co 2+ = 0.058 nm, a Zn 2+ = 0.06 nm).…”

“…Experimental and theoretical studies suggest that substitution ZnO with transitional metal elements (M-ZnO) such as Mn, Ce, Co, Ni, and Al can improve optical, electrical, and thermoelectric properties. [17][18][19][20][21][22][23][24][25][26][27] Cobalt has received much recognition as a candidate material because the ionic radius of Co 2+ is close to that of Zn 2+ (a Co 2+ = 0.058 nm, a Zn 2+ = 0.06 nm). It can be a substitute in the host lattice without disturbing the crystalline structure.…”

ZnO thin film-nanowire array homo-structures with tunable photoluminescence and optical band gap

“…The low wavenumber peak at 330 cm À1 has been interpreted earlier as being a second order Raman scattering peak originating from multi-phonon scattering processes. [29][30][31] This is ascribed to the E 2 (high)-E 2 (low) mode of ZnO, related to the zone boundary phonons, similar to GaN. 31 The presence of these modes in un-doped ZnO thin lms is unusual, since majority of the observations on this low wavenumber peak have been in the case of metal-doped ZnO.…”