Dissertation > Excellent graduate degree dissertation topics show

Investigation on Pulsed Laser Deposited Doped ZnO-Based Thin Films and Their Related Devices

Author: CaoLing
Tutor: ZhuLiPing
School: Zhejiang University
Course: Materials Physics and Chemistry
Keywords: ZnO thin films ZnMgO thin films P-type doping Transparent conducting thin films Optoelectronic property First-principles calculation Pulsed laser deposition
CLC: TN304.21
Type: PhD thesis
Year: 2012
Downloads: 183
Quote: 2
Read: Download Dissertation

Abstract


Zinc oxide (ZnO), as a novel oxide semiconductor with a direct band-gap structure, has been considered as a very promising material for the next-generation short-wavelength optoelectronic devices, such as light-emitting diodes (LEDs) and laser diodes (LDs) due to a wide band-gap of 3.37 eV and a large excition binding energy of 60 meV. To realize these device applications, an imperative issue is to fabrication both high-qulity n-and p-type ZnO. Most of the previous studies related to ZnO-based transparent conducting thin films were carried out using metallic cation dopants such as Group IIIA (e.g., Al, Ga, and In). However, fluorine can be a promising n-type anion doping candidate. To the best of our knowledge, research on F-doped ZnO thin films is very limited. Therefore, we carried out some investigation on fluorine-doped ZnO transparent conducting thin films. On the other hand, it has proven to be difficulty in obtain high-quality, reproducible, and stable p-type doping in ZnO caused by the asymmetric doping limitation, which is the bottleneck of realizing such optoelectronic applications. Also, the optimal choice of acceptor species in ZnO remains to be determined. In this regard, the main work was focused on pursuing the appropriate doping species and doping techniques in p-type ZnO thin films in this dissertation, in an attempt to better understand the p-type doping mechanism by a combinatorial theory and experimental studies. The main work included:1. Highly transparent and conducting fluorine-doped ZnO thin films were prepared on glass substrates by pulsed laser deposition. The effects of oxygen pressure on the structural, electrical and optical properties of the films were investigated and discussed in detail. The minimum resistivity of 4.83x10"4Ω-cm. with a carrier concentration of 5.43×1020cm-3 and a Hall mobility of 23.8 cm2V"’s"’, were obtained for fluorine-doped ZnO film prepared at the optimal oxygen pressure of 0.1 Pa. The average optical transmittance in the entire visible wavelength region was higher than 90%and the transmittance in 1500 nm was about 60%. In addition, a top-gated transparent ZnO-based thin-film transistor with a ZnO layer as the channel. Ta2O5 as the gate insulator and F-doped ZnO film as the gate/source/drain electrodes has been prepared.2. We realized the p-type ZnO thin films via Li-F codoping technique prepared by pulsed laser deposition. The effects of substrate temperature on the structural and electrical properties of the films were investigated in detail. An acceptable p-type conduction, with a resistivity of 23.45Ωcm. a Hall mobility of 0.35 cm3v-1s-1, and a hole concentration of 7.57x1017 cm-3 at room temperature, has been obtained for the Li-F codoped ZnO thin films grown at 550℃The possible formation mechanism of the p-type conduction in Li-F codoped ZnO has been proposed by first-principles calculations based on density functional theory.3. We reported on p-type Ag-doped ZnMgO thin films prepared on quartz substrates by pulsed laser deposition. The effects of substrate temperature on the structural, electrical and optical properties of the films were investigated in detail. XPS measurement confirmed that Ag principally occupies Zn site in the state of Ag+ ion and acts as an acceptor. An acceptable p-type conduction, with a resistivity of 24.96Ωcm. a Hall mobility of 0.32 cm2v-1s-1.and hole concentration of 7.89x1017 cm-3 at room temperature, was obtained for the film grown at the optimal substrate temperature of 400℃Meanwhile, a comparative study of p-type ZnO.Ag and ZnMgO:Ag films showed that the incorporation of Mg can result in the increase of the activation energy of the intrinsic donors and the suppression of charge-compensating oxygen-related defects, thus reduce the charge compensation effect of intrinsic defects, which is favorable to the realization of p-type ZnO thin films.

Related Dissertations

  1. Iron-doped SnO \u003csub\u003e 2 \u003c/ sub\u003e ceramics and thin films research,TQ174.6
  2. First-Principles Studies of Blacl Phosphorus and LiMn2O4 as Electrode Material for Lithium Ion Batteries,TM912
  3. Tailoring In-plane Crystallographic Orientation of Epitaxial YBa2Cu3O7-δ Thin Films Having Perpendicular C-axes Texture,TB383.2
  4. The Epitaxial Growth of C-axis Oriented YBa2Cu3O7-δ Films by Pulsed Laser Deposition and the Elimination of Laser-induced Particles,TB383.2
  5. First-principles Investigation on the Structures and Properties of BiFeO3,TB34
  6. A Study on Highly Oriented AlN Thin Film Prepared by Pulsed Laser Deposition,O484.1
  7. Preparation and Properties of Zinc Oxide and Aluminum Doped Zinc Oxide Thin Films,O484.1
  8. Study on the Photoelectrocatalytic Degradation of Nitrogen-containing Organic Pollutants with ZnO Thin-films Prepared by Sol-gel Method,X703
  9. Pulsed Laser Deposition of Niobium Doped Tio2 as Transparent Conducting Films,TN249
  10. TC4 alloy pulsed laser deposition of hydroxyapatite microstructure and properties of,TG146.23
  11. ZnO nanocrystalline structure of the film luminescence and doping,O484
  12. Preparations and Optical Properties of Zn1-x CoxO and Ti1-xHoxO2 Films,O484.41
  13. Synthesis and Characterization of ZnO Films by Ultrasonic Spray Pyrolysis,TB43
  14. Preparation of phase separation of the amorphous silicon oxide and nanocrystalline silicon mosaic silica,TN304.1
  15. Research of ZnO Thin Films for SAW Resonator,TN304.055
  16. Fabrication Characterization, and Photovoltaic Application of Semiconducting Fe2O3 Thin Films Deposited by Pulsed Laser Deposition,O484.1
  17. The Exploration on Electroluminescence of ZnO Thin Films,O484.41
  18. Preparation and characterization of silicon LiNbO_3 piezoelectric thin film multilayer structure,O484.1
  19. Preparation and Properties of Ca-Co-O system oxide thermoelectric materials,TB34
  20. Preparation of MnSi1.7 Thermoelectric Material and Calculations of Its Electronic Structure,TB34
  21. Preparation and Properties of Bi-based Co-based oxide of thermoelectric ceramic and film,TQ174.1

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