Dissertation > Excellent graduate degree dissertation topics show

Study of MOCVD Growth of p-ZnMgO:as Films and the Light Emitting Devices

Author: ZhaoLong
Tutor: ZhangBaoLin
School: Jilin University
Course: Physical Electronics
Keywords: MOCVD ZnMgO As doping heterojunction light emitting device
CLC: TN304.055
Type: Master's thesis
Year: 2012
Downloads: 32
Quote: 1
Read: Download Dissertation

Abstract


ZnO is a direct wide bandgap semiconductor, the bandgap is about3.37eV at room temperature, and the exciton binding energy is60meV, far higher than room thermal ionization energy (26meV). Therefore, it can achieve high efficiency ultraviolet radiation luminescence at room temperature or higher temperature. This makes ZnO has important application in the preparation of ultraviolet light emitting diodes (LEDs) and laser devices (LDs). ZnO not only has some similar properties with GaN such as band gap, lattice constant and the thermal expansion coefficient, but also has some advantage which GaN doesn’t have. As the third generation semiconductor materials ZnO shows great potential applications together with the GaN material.With in-depth study of ZnO material using in UV wavelength LEDs and LDs, people begin to pay attention to ZnMgO material. ZnMgO is formed by ZnO and MgO in a certain component. The same valence state of Mg atom and Zinc atom won’t cause changes in carrier concentration, and the magnesium ions (Mg2+) radius (0.57A) is very close to the size of the zinc ions (Zn2+) radius (0.60A), which makes lattice mismatch caused by MgZn be very small, only0.1%. And the introduction of Mg makes the band gap of ZnO be continuously adjusted in the range of3.3-7.8eV. ZnMgO can also combine with ZnO to produce ZnO/ZnMgO superlattices, quantum wells and deep UV devices. But as the same as ZnO, the p-type doping problem of ZnMgO is also not well resolved, which makes exploring new method of preparing p-ZnMgO has very important scientific significance. In this thesis, we adopt metal organic chemical vapor deposition (MOCVD) technology, innovative use the sputtered GaAs interlayer as the acceptor doping source, successfully prepared p-ZnMgO:As films. And we also fabricate the p-ZnMgO/n-GaN light emitting devices. The specific work includes the following:(1) The preparation of high-quality ZnMgO films. The ZnMgO film was deposited on sapphire substrates by MOCVD technology. We detailed discussied the impact of growth temperature on film quality, and find the optimum growth temperature. To further improve the ZnMgO film quality, reduce the lattice mismatch and thermal mismatch between ZnMgO film and the substrate, ZnO buffer layer was introduced.By adjusting the growth temperature of buffer layer, we prepared high quality ZnMgO film finally.(2) The p-type doping of ZnMgO films. Through the analysis of several p-type doping mechanism, we chose the V group elements As as the dopant. Innovative introduced the sputtering GaAs interlayer to achieve As doping p-ZnMgO films. Through a set of variable temperature growth experiments, the propeties of ZnMgO:As were discussed in detail. The minimum resistivity p-ZnMgO film was26.33Ω·cm, with the carrier concentration was1.638x1017cm-3, mobility was1.45. X-ray diffraction (XRD) and photoluminescence (PL) test showed that the preparation of high temperature p-ZnMgO film had more good crystalline quality and optical quality.(3) The fabrication of n-GaN/p-ZnMgO heterojunction device and the study of its electroluminescence characteristics. First, the carrier concentration of5×1018cm-3n-GaN substrate was selected, and then p-ZnMgO:As film was prepared by sputtering GaAs interlayer, the order of carrier concentration was1017cm-3and then proceed to the fabrication of the device. The electroluminescence (EL) test showed that the heterojunction device had excellent electroluminescent properties, and the emitting area is mainly concentrated in the376nm in ultraviolet region, when the injection current reached150mA, the UV/visible ratio luminous intensity as high as35.

Related Dissertations

  1. Preparation and Photocatalytic Properties for Water Decomposition of Titanate Photocatalyst,O643.36
  2. The Study of Preparation and Photocatalytic Activity of TiO2 by Electrospinning,O614.411
  3. Study and Preparation of BaTiO3-based NTC Ceramic Thermistors,TQ174.1
  4. First- principles calculations of doped anatase titanium dioxide photocatalytic properties,O643.36
  5. Preparation of One-dimensional Nano TiO2 and Study on the Decolorization of Dyeing Wastewater,TB383.1
  6. First-Principles Studies of Cathode Material LiMO2 （M=Co, Ni, Mn） of Lithium Ion Batteries,TM912
  7. Iron, lanthanum -doped nano TiO \u003csub\u003e 2 \u003c/ sub\u003e Preparation and photocatalytic properties,O614.411
  8. First-Principles Study of Si/Ge Adsorption on Doping Graphene,O469
  9. Na, K and Mg of preparation and properties of doped ZnO thin films,TB383.2
  10. Influence of Doping Effect on Zinc Oxide by First Principles Studies,O614.241
  11. Study on Microstructure and Superconducting Properties of MgB2 Wires Fabricated by Two-Step PIT,TM26
  12. Preparation and Photocatalytic Properties of Rare Earth Doped TiO2 and ZnWO4 with Different Morphologies,O643.36
  13. Magnetocaloric Effect in Pure and Doped Magnetic Relaxor Ferroelectrics CdCr2S4,O482.5
  14. Porous MIn 2 S 4 (M = Zn, Cd) photocatalyst Preparation, Characterization and Photocatalytic Performance,O643.36
  15. Preparation and Surface Functionalization of Mg-doped ZnO Quantum Dots,O614.241
  16. First-Principle Studies of Cathode Materials LiFePO4 and Its Doped Systems for Lithium Ion Batteries,TM912
  17. Study on the Photoluminescence Properties of the Rare Earth Doped Oxide Phosphors Prepared by Hydrothermal Method,TQ422
  18. Synthesis and Electrochemical Performances of New Lithium-ion Battery Cathode Materials Li3V2（PO4 ）3 and Li[NixLi1/3-2x/3 Mn 2/3-x/3)O2,TM912
  19. Preparation and Characterization of Nano-sized TiO2 Powder and Ceramics,TB383.1
  20. The Preparation and Photoelectric Properties of ZnO/GaN Heterojunction Light-emitting Diode,TN312.8
  21. Study on Preparation of Novel Modified TiO2 Photocatalyst for Photodegradation of Organic Pollutants,O643.36

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