Optical properties of GaAs:Mn nanowires

Katarzyna Gas 1Janusz Sadowski 1,2Jean-Francois Morhange 3Aloyzas Siusys 1Wojciech Zaleszczyk 1Tomasz Wojciechowski 1Takeshi Kasama 4Abdulmenaf Altintaş 5Hongqi Xu 5,6Wojciech Szuszkiewicz 1

1. Polish Academy of Sciences, Institute of Physics, Lotnikow 32/46, Warsaw 02-668, Poland
2. Lund University, MAX-lab, Lund SE-221 00, Sweden
3. Institut des nanosciences de Paris (INSP), 140 rue de Lourmel, Paris 75015, France
4. Center for Electron Nanoscopy, TUD, Kongens Lyngby DK-2800, Denmark
5. Division of Solid State Physics and the Nanometer Structure Consortium, Lund University, Box 118, Lund SE-221 00, Sweden
6. Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics, Peking University, Beijing 100871, China

Abstract
GaAs nanowires (NWs) are attractive for potential applications in nanodevices, since they are built from a material which is widely used in optoelectronics. For functional devices the control over the polarity and concentration of charge carriers, i.e., doping of the given semiconducting materials is essential. Particularly interesting is doping of GaAs NWs with Mn. In GaAs the Mn2+ ions occupy Ga sites. They provide magnetic moments, due to the spin polarisation of the half filled 3d shell, and act as effective acceptors. Such behaviour opens the possibility of using Mn-doped GaAs NWs for studying interesting phenomena associated with interactions between charge carriers or photons with localized, single Mn spins.

In this work we focus on optical properties of GaAs:Mn NWs measured by photoluminescence (PL), cathodoluminescence (CL) and micro Raman scattering (μ-RS). The NWs were grown in self-catalytic growth mode on oxidized Si(100) surface by MBE and characterized by SEM, TEM, and electron transport measurements. In order to analyze the influence of Mn on the physical properties of NWs the undoped GaAs NWs obtained in otherwise exactly the same manner as those containing Mn were also investigated. The NWs are quite uniform in terms of sizes (diameters and lengths being close to 150 nm and 5 μm, respectively) – see Figure 1. A slight decrease of the NW diameter with an increasing distance from the NW top can be noticed.

Figure 1. Scanning electron microscopy images of GaAs:Mn nanowires grown on Si(100).

Figure 2. Low temperature PL spectra (normalized to the highest intensity) for GaAs:Mn NWs at different excitations (532 nm and 325 nm laser lines). The inset shows the low temperature PL spectrum of GaAs NWs at excitation of 532 nm laser line.

The comparision of PL spectra measured for GaAs and GaAs:Mn NWs is presented in Figure 2. The transitions related to the Si impurities, introduced into NWs from the substrate during the growth, are present both in undoped and Mn-doped NWs. In the latter case a transition at 1.41 eV associated with Mn acceptor states was also detected. This is a direct proof that the Mn2+ acceptors are located at Ga sites of the GaAs host lattice of the NWs. CL measurements performed on the single NW proved definitely that the PL signal came from the NWs only, not from the sample surface between them. An anomalous temperature dependence of the exciton emission was also found for GaAs:Mn NWs and explained by the thermal activation of Mn acceptor states. The μ-RS spectra, taken for the single NW revealed that the Mn concentration in GaAs:Mn NWs should not exceed 0.05% (1•1019 cm-3). This value is much lower than the Mn/Ga flux ratio (about 3%) applied during the MBE growth. For both GaAs and GaAs:Mn the structures resulting from surface optical phonon modes were also found. The results of resistivity measurements as a function of temperature showed that contrary to undoped GaAs NWs the Mn doped ones are conductive. The p-type of this conductivity confirms the acceptor character of Mn impurities embedded into NW. The direct evidence that a substantial accumulation of Mn takes place inside the catalyzing Ga droplets at the top of the nanowires only was also found by TEM investigation.

This work was partially supported by the EU within European Regional Development Fund through grant Innovative Economy (POIG.01.01.02-00-008/08) and by the grant N N202 128639 from the Ministry of Science and Higher Education (Poland).

[1] K. Gas, J. Sadowski, J.F. Morhange, A. Siusys, W. Zaleszczyk, T. Wojciechowski, T. Kasama, A. Altintaş, H. Q. Xu, and W. Szuszkiewicz, sent to Nanoscale

 

Related papers
  1. Phase Transfer Catalyzed Dialkylation of Sterically Hindered Arylacetonitriles
  2. Critical exponents of dilute ferromagnetic semiconductors (Ga,Mn)N and (Ga,Mn)As
  3. Neutron scattering studies of short-period MnTe/ZnTe superlattices: magnetic order, magnon propagation and confinement
  4. X-ray diffraction studies of (Pb,Cd)Te solid solution – possible new material for thermoelectric applications
  5. Optical Characterisation of Bulk ZnO Crystals Grown by CVT
  6. Hexagonal MnTe with NiAs structure: thermal expansion coefficients and exchange striction
  7. 1D ZnO-based structures obtained by thermal oxidation of ZnTe and ZnTe/Zn nanowires
  8. Photoreflectance study of Ga(Bi,As) and (Ga,Mn)As epitaxial layers grown under tensile and compressive strain
  9. Physical properties of unique ZnO single crystals from Oława Foundry
  10. MBE growth, structural, magnetic, and electric properties of (In,Ga)As-(Ga,Mn)As core-shell nanowires
  11. Quaternary (Ga,Mn)BiAs ferromagnetic semiconductor -MBE growth, structural and magnetic properties
  12. Up-conversion and down-conversion processes observed in Er3+, Yb3+ and Mn2+ doped ZnAl2O4 nanoparticles
  13. Synthesis and properties of up-converted NaYF4: Er, Yb nanoparticles for biomedical applications
  14. Synthesis and properties of NaYF4: Er, Yb, Gd nanoparticles with and without SiO2 coating for biomedical applications.
  15. Designing biosensors based on semiconductor nanoparticles for an early detection of neurodegenerative diseases.
  16. Stany Mn 3d w paśmie walencyjnym Ga1-xMnxSb
  17. Low-temperature expansion of metastable Pb1-xCdxTe solid solution
  18. Can we control the process of room temperature ferromagnetic clusters formation in GaMnAs matrix?
  19. Structural transformations of GaMnAs layer annealed under enhanced hydrostatic pressure
  20. Raman spectroscopy of ZnTe-based nanowires grown by MBE *
  21. Optical phonon dispersion for zinc-blende semiconductors
  22. Raman spectroscopy and magnetic properties of bulk Zn0984Co0.016O crystal
  23. Electronic structure of Mn atoms in (Ga,Mn)As layers modified by high temperature annealing
  24. Effect of high pressure annealing on defect structure of GaMnAs
  25. Influence of high temperature annealing on the local atomic structure around Mn atoms and magnetic properties of (Ga,Mn)As layers
  26. Catalytic growth by molecular beam epitaxy and properties of ZnTe-based semiconductor nanowires
  27. Effect of stress on structural transformations in GaMnAs
  28. Tunneling Anisotropic Magnetoresistance effect in p+-(Ga,Mn)As/n+-GaAs Esaki diode structure.
  29. Formation of epitaxial MnSb and MnBi layers on GaMnAs
  30. Magnetotransport properties of ultrathin GaMnAs layers
  31. Giant planar Hall effect in ferromagnetic (Ga,Mn)As layers
  32. Magneto-conductance through nanoconstriction in ferromagnetic (Ga,Mn)As film
  33. Promising high quality short period Fe/Fe-N multilayers deposited by the sputtering
  34. Magnetic stripe domains in Fe/Fe-N multilayers
  35. Low-frequency magnons and phonons in hexagonal MnTe
  36. Folded Acoustic phonons in (CdTe)n/(MnTe)m superlattices
  37. Area detector as a tool to study properties of the magnetic multilayers by the neutron scattering
  38. Influence of hydrogen adsorption on magnetic properties of Fe films and multilayers
  39. Defects in GaMnAs - influence of annealing and growth conditions
  40. Photoemission study of the LT-GaAs
  41. High-pressure phase transition and compressibility of zinc-blende HgZnSe mixed crystals
  42. Structure characterisation of MBE-grown ZnSe:Cr layers
  43. Gallium nitride surface formation and modification by Mn deposition - photoemission studies with use of synchrotron radiation
  44. Lattice parameters changes of GaMnAs layers induced by annealing

Presentation: Oral at 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17, Topical Session 2, by Katarzyna Gas
See On-line Journal of 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17

Submitted: 2013-04-15 22:10
Revised:   2013-05-01 22:21