Growth and characterisation of cobalt doped zinc oxide 7

... XRD and TEM data suggested that, although Co clusters had been formed in heavily co -doped samples, the dominant phase of these samples was still in the form of Co -doped ZnO The formation of substitutional ... composition for formation of secondary phases and Co clusters could be identified clearly On the other hand, the shape of the MR curves for heavily doped samples rese...

Ngày tải lên: 12/09/2015, 08:19

... semiconductor”, Adv Mater 16 , 211 5 (2004) 12 1 S Ramachandran, A Tiwari, and J Narayani, “Origin of room-temperature ferromagnetism in cobalt- doped ZnO”, J Electronic Mater 33, 12 98 (2004) 12 2 H J Lee, G ... properties of Co -doped ZnO nanoparticles”, Appl Phys Lett 86, 10 311 3 (2005) 75 J S Hong and R Q Wu, “Magnetic ordering and x-ray magnetic circular dichroism of...

Ngày tải lên: 12/09/2015, 08:18

... (Zn0.75Co0 .25 O + CoO + Co) structures, respectively [After J H Kim, 20 02, Ref 12] 50 Chapter Cobalt doped zinc oxide 2. 3 .2. 2 Choice of dopants As ZnO can be both p-type and n-type doped, the choice of ... 1 725 02 (20 06) 72 Chapter Cobalt doped zinc oxide 22 K Sato and H K Yoshida, “Stabilization of ferromagnetic states by electron doping in Fe-, Co- or...

Ngày tải lên: 12/09/2015, 08:18

... s for -doped samples at a sputtering power of 10 W For the co -doped samples, Co was added to ZnO:Al by co-sputtering Co with ZnO and Al2O3 On the other hand, in -doped samples, Co was doped “digitally” ... Al2O3 Substrate e) Deposit Al2O3, Lift-off f) Ion-mill to form Hall bar Al2O3 Substrate Al2O3 Substrate g) Coat resist h) Write electrodes, develop Al2O3 Substrate Al2O3 Substrate...

Ngày tải lên: 12/09/2015, 08:18

... the peak at 44 .5o was near peak positions of CoO (200) 107 Chapter Structural Characterization FCC at 40 .6o and 42 .4o, Co (111) at 44 .217o, ZnCo2O4 (40 0) at 44 .74o and Co3O4 (40 0) at 44 .81o For ... state of Co in ZnCo2O4 and Co3O4 was 3+ and 4+ , and that in Co clusters was 0, respectively In comparison, the corresponding δ -doped Co98s sample, showed a variation...

Ngày tải lên: 12/09/2015, 08:18

... formation of other secondary phases 133 Chapter Magnetic properties and its origins 0. 05 0.10 0. 15 0.20 0. 25 0.30 0. 35 0. 05 0.10 0. 15 0.20 0. 25 0.30 0. 35 Figure 5- 4 (a) In-plane M-H curves of co -doped ... in-plane and out -of- plane configuration and corrected M-H curves (b), (d) and (f) respectively Out -of- plane M-H curves for co -doped sample Co3W (Zn0.95C...

Ngày tải lên: 12/09/2015, 08:19

... (Ohm) 1 .66 E+022 1 .66 ×10 1 .64 E+022 1 .64 ×10 (c) 1 .62 E+022 1 .62 ×10 1 .60 E+022 1 .60 ×10 1.58×10 1.58E+022 1. 56 102 1.56E+02 -0.04 -0.02 0.02 0.04 Field (T) Figure 6- 13 dI/dV curves as a function of bias ... in Co -doped samples 150 Chapter Origin of ferromagnetism from transport studies 1. 966 20K 1. 964 -3 1. 962 10K 8K 1. 960 6K 1.958 (a) -2 50K 7 .62 30K 7 .60 10K 7.58 4....

Ngày tải lên: 12/09/2015, 08:19

... 1.1 Zinc Oxide 1.1.1 The Structure of Zinc Oxide 1.1.2 The Properties of Zinc Oxide 1.1.3 Applications of Zinc Oxide 1.1.4 Doping of Zinc Oxide ... in un -doped and Mn -doped ZnO [9] Obviously, the change in the optical properties is strongly dependent on the method of incorporation of Mn, fabrication conditions, and properties of un -doped .....

Ngày tải lên: 06/10/2015, 20:42

... Structural, optical, and magnetic studies of manganese-doped zinc oxide hierarchical microspheres by self-assembly of nanoparticles Yao-Ming Hao1, Shi-Yun ... study, a series of manganese [Mn]-doped zinc oxide [ZnO] hierarchical microspheres [HMSs] are prepared by hydrothermal method only using zinc acetate and manganese acetate as precursors and e...

Ngày tải lên: 20/06/2014, 20:20

... Structural, optical, and magnetic studies of manganese-doped zinc oxide hierarchical microspheres by self-assembly of nanoparticles Yao-Ming Hao1, Shi-Yun ... study, a series of manganese [Mn]-doped zinc oxide [ZnO] hierarchical microspheres [HMSs] are prepared by hydrothermal method only using zinc acetate and manganese acetate as precursors and e...

Ngày tải lên: 21/06/2014, 17:20

... Adatom to graphene charge transfer (e) Reference Hole 1. 27 2 .12 - 1. 31) - 81 Hole 1. 32 2.09 1. 56 1. 1 1. 1 83 Hole 0.97 - 1. 51 1.0 0.6 33 Hole 2.4 - 1. 52 1. 0 0.2 31 Hole 1. 58 2 .10 1. 49 1. 0 - 32 ... from the SiC bulk so that the (63x63)R30o of SiC(00 01) coincidence with 13 x13 of the graphene mesh Due to mismatch between the SiC(1x1) and graphene( 1x1)...

Ngày tải lên: 11/09/2015, 09:58

... time-dependence of adatoms density, n1 (cm-2s-1) on substrate is assumed to be of first-order† and is given as [13]:   dn1 n   F   2 1n1   i ni  2 2 n2   i ni dt  i 2 i 3 (2. 2) where ... atomistic model of nucleation in Eq (2. 8) can be applied to understand dynamics of surface nucleation and growth According to Eqs (2. 8) and (2. 8a), i* (or E) can be e...

Ngày tải lên: 11/09/2015, 09:58

... Chapter 3. 3.2 Growth of Co on HOPG, (63x6 3) R30o and graphene Co was evaporated on HOPG, 6 3 and graphene using Omicron’s e-beam evaporator Various fluxes from 10 -3 to 10-2 ML/s were used for growth ... each other (see Fig 3. 13a) For VW growth (3D islands), a plot with single gradient across all the coverage is observed (see Fig 3. 13b) since the thickness of 3D g...

Ngày tải lên: 11/09/2015, 09:58

... shows graphene lattice; (c) and (d) distributions of cluster volume on 63 and graphene terrace respectively; and (e) line profiles of unadorned area of 63 (blue) and graphene (dotted line) Fig 4. 17a ... SiC 4. 2Å SiC SiC SiC 3.3Å 4. 2Å 3.3Å SiC SiC SiC SiC SiC SiC 3.3Å Fig 4. 27 Mechanism in Fig 4. 24 and 4. 26 are extended for third layer graphene formation...

Ngày tải lên: 11/09/2015, 09:59

... 50 o h 350 eV 50 o C 1s h 350 eV 50 o o 50 153 Intensity (a.u.) Intensity (a.u.) 2 85 B2 0o C6 C5 0o B1 30 Co 156 154 152 Binding energy (eV) 10 Co Co Graphene 158 30 Co 10 Co C4 C3 C2 Co 150 Graphene ... Adsorption of Co at room temperature (a) (b) 50 o Co 3p h 350 eV 50 o Si 2p h 350 eV 60 50 o 102 A1 o Intensity (a.u.) Intensity (a.u.) 50 0o 0o 30 Co 30 Co 10 Co Co Grap...

Ngày tải lên: 11/09/2015, 09:59