Dissertation > Excellent graduate degree dissertation topics show

Preparation of ZnO Diluted Magnetic Semiconductors by Hydrothermal Method

Author: LiHuiQin
Tutor: MiaoHongYan
School: Shaanxi University of Science and Technology
Course: Materials Physics and Chemistry
Keywords: Diluted magnetic semiconductors ZnO Hydrothermal Synthesis Magnetic properties
CLC: TN304
Type: Master's thesis
Year: 2008
Downloads: 177
Quote: 1
Read: Download Dissertation

Abstract


Diluted magnetic semiconductor material (Diluted Magnetic Semiconductors-DMSs) has both properties and spin properties of the electron charge, the basis of spintronics having excellent magnetic, magneto-optical, magnetic and electric properties, it in high density nonvolatile volatile memory, magnetic sensors, semiconductor integrated circuits, semiconductor lasers and spin quantum computer field has broad application prospects. Experiment ZnO as a substrate by hydrothermal method respectively were the Ni 2 Cr 3 , the Co. 2 and Mn 2 doping of ZnO based diluted magnetic semiconductor powders. Discussed the preparation of the precursor, mixing time, the impact of technological factors on the reaction temperature, reaction time, and the type and concentration of the mineralizer doped content powder preparation. Powder XRD characterization crystal phase of the sample analysis of a scanning electron microscope, observation of the microstructure of the powder; test the absorption of the dopant ions by UV absorption peak, and can be detected through the forbidden band width calculated doped ZnO the influence of the electrical properties; magnetic properties of the hysteresis loop of the hysteresis loop test ZnO-based diluted magnetic semiconductor materials, analysis of materials; doping analysis by the EDS test the actual content. Ni 2 -doped ZnO, NaOH as a mineralizing agent is more suitable than KOH doped; mineralizing agent concentration of a high concentration, there are conducive to the formation of a pure crystal, 3mol / L appropriate; However, mineralizing agent concentration should not be too high, when the concentration of 5mol / L, the emergence of Ni (OH) 2 impurity phase. Different doping content is discussed the influence of the sample was prepared, and when x = 0.05 and 0.1 to give a pure crystalline phase; when the doping content order of x = 0,0.05,0.1,0.2, the forbidden band width decreased first increased, respectively, as 3.20eV, 3.19eV, 3.15eV, 3.17eV. Precipitation and Sol-gel prepared precursor precipitation prepared precursor powders were synthesized by hydrothermal ideal can get pure Zn0.95Ni0.05O samples, XRD and UV-Vis confirmed Ni 2 replace Zn 2 , crystal ferromagnetic the actual doping content of 3.20% (Atomic%). For Cr 3 ion doped ZnO NaOH do mineralizing agent than KOH is more conducive to doping; elevated reaction temperatures favor doped at 240 ℃ is appropriate; reaction time was 24h, stirring time is 7 ~ 8h favor synthesis of small particles of grain;, will appear when the doping content increases the impurity phase ZnO solid solution of Cr ions is limited; mineralization agent 3mol / L The better performance of the NaOH, the filling rate of 75%, when the doping amount of Cr is not higher than 0.15mol ratio available dilute magnetic semiconductor XRD tests showed that with the limited amount of Cr ion doping, when x ≤ 0.15, doped into the lattice of the ZnO, and the preparation of crystal growth is relatively complete. Can be observed from the FE-SEM, doping amount x ≥ 0.2, the crystal morphology from the short columnar into long columnar. By the hysteresis loop crystal exhibits paramagnetism. For Co 2 -doped ZnO, and, can be synthesized a relatively pure Zn0.95Co0.05O and Zn0.9Co0.1O crystal phase under conditions of 200 ° C and 240 ℃ the; UV-Vis test found at 570nm , 610nm and 655 nm at the absorption peak of the Co ions, Co ions doped into the crystal lattice of the ZnO; paramagnetic at room temperature, the crystal exhibits. Mn 2 -doped ZnO concentration of mineralizing agent affect the concentration of the product, as a mineralizing agent to 3mol / L of NaOH to synthesize a pure Zn 0.95 Mn the 0.05 O and Zn , 0.9 Mn 0.1 O crystal phase; to 5mol / L NaOH as a mineralizing agent, can be synthesized Zn 0.85 Mn 0.15 O crystals. Room temperature, Zn 0.9 Mn 0.1 O and Zn 0.85 Mn 0.15 O crystal exhibits ferromagnetism.

Related Dissertations

  1. Hydrothermal Synthesis of Oxide Hollow Spheres,TB383.4
  2. Study on the Chimisorption Removal of FCC Gasoline Sulfur Compound,TE624.55
  3. Flexible,rigid,Synthesis and characterization of mixed ligand complexes,O621.1
  4. Preparation of ZnO -based microemulsion photocatalytic material,O614.241
  5. 1,3 - propanediamine shrink o-vanillin 3d-4f heteronuclear bimetallic complexes synthesis, structure and properties of,O627.3
  6. Syntheses, Structures and Properties of Coordination Polymers with Aromatic Dicarboxylates,O631.1
  7. Syntheses, Structures and Properties of Metal-organic Coordination Polymers Based on Long-Chain Aromaticmulticarboxylate,O631.3
  8. Influence of Doping Effect on Zinc Oxide by First Principles Studies,O614.241
  9. Fabrication, Defect Manipulation and Optical Properties of ZnO Hybrid Materials,TB33
  10. Preparation and Characterization of Multifunctional Fe3O4/ZnO/SiIO2 Nanocomposites,TB383.1
  11. Hydrogen Evolution Process of Water Electrolysis Assisted by TiO2 Nanotubes and TiO2/ZnO Nanorodes Assembled on Ni Substrate,TQ116.21
  12. Preparation and Properties of ZnO-based Diluted Magnetic Semiconductors,TN304.21
  13. The Study of Si Surface Adsorption and Magnetism of Si-Doped Defect in GaN,TN304.12
  14. Sol - gel method p -type ZnO films,O484.1
  15. Synthesis and Characterization of ZnO Films by Ultrasonic Spray Pyrolysis,TB43
  16. Research of ZnO Thin Films for SAW Resonator,TN304.055
  17. Preparation and Physical Properties of Mn and Co-doped SiC Diluted Magnetic Semiconductor Films,TN304.055
  18. Study on the Preparation and Doping Y2O3 of Low-voltage ZnO Varistor Ceramics,TN304.93
  19. Doped ZnO thin film magnetic materials Preparation and magnetic properties at room temperature,O484.1
  20. Hydrogen AlN and ZnO-based diluted magnetic semiconductor materials First-principles study,O471
  21. The Exploration on Electroluminescence of ZnO Thin Films,O484.41

CLC: > Industrial Technology > Radio electronics, telecommunications technology > Semiconductor technology > General issues > Material
© 2012 www.DissertationTopic.Net  Mobile