A new route toward semiconductor nanospintronics: highly Mn-doped GaAs nanowires realized by ion-implantation under dynamic annealing conditions.

Institute for Solid State Physics, Jena University, Max-Wien-Platz 1, 07743 Jena, Germany.
Nano Letters (Impact Factor: 13.03). 08/2011; 11(9):3935-40. DOI: 10.1021/nl2021653
Source: PubMed

ABSTRACT We report on highly Mn-doped GaAs nanowires (NWs) of high crystalline quality fabricated by ion beam implantation, a technique that allows doping concentrations beyond the equilibrium solubility limit. We studied two approaches for the preparation of Mn-doped GaAs NWs: First, ion implantation at room temperature with subsequent annealing resulted in polycrystalline NWs and phase segregation of MnAs and GaAs. The second approach was ion implantation at elevated temperatures. In this case, the single-crystallinity of the GaAs NWs was maintained, and crystalline, highly Mn-doped GaAs NWs were obtained. The electrical resistance of such NWs dropped with increasing temperature (activation energy about 70 meV). Corresponding magnetoresistance measurements showed a decrease at low temperatures, indicating paramagnetism. Our findings suggest possibilities for future applications where dense arrays of GaMnAs nanowires may be used as a new kind of magnetic material system.

1 Bookmark
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We simulated and experimentally investigated the sputter yield of ZnO and GaAs nanowires, which were implanted with energetic Mn ions at room temperature. The resulting thinning of the nanowires and the dopant concentration with increasing Mn ion fluency were measured by accurate scanning electron microscopy (SEM) and nano-X-Ray Fluorescence (nanoXRF) quantification, respectively. We observed a clear enhanced sputter yield for the irradiated nanowires compared to bulk, which is also corroborated by iradina simulations. These show a maximum if the ion range matches the nanowire diameter. As a consequence of the erosion thinning of the nanowire, the incorporation of the Mn dopants is also enhanced and increases non-linearly with increasing ion fluency.
    Journal of Physics D Applied Physics 09/2014; 47(39). DOI:10.1088/0022-3727/47/39/394003 · 2.52 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The authors report on the differences in ferromagnetic MnAs nanocluster formation on GaAs, GaAs/AlGaAs, GaAs/GaAsP, and InAs nanowire templates by combing selective-area metal-organic vapor phase epitaxy of semiconducting nanowires and endotaxial nanoclustering of MnAs. To characterize the dependences of MnAs nanocluster formation on semiconducting materials of the nanowire templates, GaAs, GaAs/AlGaAs core-shell, and GaAs/GaAsP core-shell nanowires have been grown at 750 °C, whereas InAs nanowires have been grown at 580 °C. MnAs nanoclusters are commonly and most frequently formed at six ridges between two {0-11} crystal facets on hexagonal prisms of III-V semiconducting nanowires. That is presumably because many atomic steps exist between the crystal facets. Here, MnAs nanoclusters are grown “into” the nanowires, as a result of the phenomenon of “endotaxy”. Manganese atoms on the nanowires surface form chemical bonds mainly with arsenic atoms of the nanowires, because only manganese organometallic source and hydrogen are supplied, i.e. no supply of arsenic hydride source during the endotaxy of MnAs. In the case of GaAs/GaAsP core-shell and InAs nanowires, however, MnAs nanoclusters are formed on the top {111}B surfaces of the nanowires, as well as at six ridges of the hexagonal prisms. The results obtained in the current work possibly show that the endotaxy of MnAs depends on the thermal stability of the nanowires and/or the strength of atomic bonds in the host materials of nanowires.
    SPIE NanoScience + Engineering; 09/2013
  • [Show abstract] [Hide abstract]
    ABSTRACT: Because of the fundamental properties and possible applications in spin-based electronics and photonics, diluted magnetic semiconductor nanowires are actively pursued. Here we report a general and facile solution synthetic strategy to prepare colloidal diluted magnetic semiconductor nanowires through solution-liquid–solid (SLS) doping approach using single-source precursors. On the basis of this strategy, transition metal ions such as Mn and Eu doped CdS nanowires were successfully synthesized and characterized. The material characterizations demonstrated that the doping process is nucleation controlled. We further investigated the Mn doping effects on nanowire growth as well as their photoluminescence properties. The Mn doped CdS nanowires exhibit photoluminescence emission related to the excitonic magnetic polaron in CdS, single Mn2+ ion and Mn–S–Mn centers as well as trap states, evidenced by the time-resolved photoluminescence spectra and magnetic measurements. With the increase of Mn precursor that used in the doping process, the Mn2+ related emission becomes more pronounced. By tuning the doping concentration, white emissive doped CdS nanowires were achieved.
    Chemistry of Materials 07/2013; 25(15):3260–3266. DOI:10.1021/cm401864d · 8.54 Impact Factor


Available from
May 21, 2014