Dissertation > Excellent graduate degree dissertation topics show

Investigation of the Magnetotransport Properties of the 2DEG in AlGaN/AlN/GaN Structure

Author: JiaoShaSha
Tutor: HaoYue
School: Xi'an University of Electronic Science and Technology
Course: Microelectronics and Solid State Electronics
Keywords: AlGaN/AlN/GaN heterostructure two-dimensional electron gas SdH oscillation effective mass
CLC: TN386
Type: Master's thesis
Year: 2011
Downloads: 162
Quote: 0
Read: Download Dissertation

Abstract


Owing to their advantages such as wide bandgap, high breakdown field and high electron saturation velocity.Ⅲ-nitride materials are an ideal candidates for high power microwave devices. Among thoseⅢ-nitride materials, AlGaN/GaN heterostructures are the new low-dimensional semiconductor material structure with large conduction-band offset and strong polarization-induced electric field. Subsequently, several experimental studies show that the insertion of the thin AlN interlayer resultes in an improvement of electrical properties. A detail study on the transport properties of the 2DEG in AlGaN/AlN/GaN heterostructures is very important in the development of the low-dimensional semiconductor physics.The magnetoresistance oscillations of semiconductor heterojunction two -dimensional electron gas（2DEG） originate from electron quantum effect, which reflecting the state density variation of Landau energy at Fermi level.We can study the magnetoresistance oscillations of two—dimensional electron gas by magnetotransport measurement, by which we can get abundant electrical character and electrons—subband property.In this dissertation, AlGaN/AlN/GaN heterostructures have been fabricated by metal-organic chemical vapor deposition（MOCVD）. Hall bar has been made by means of Stepper Scanning Photo etching Machine by three times. Ti/Al/Ni/Au Metals were evaporated by using electron beam evaporation method on the sample’s surface.After annealing alloy, ohms contact was formed. Standard,low frequency and low current, lock-in techniques were used.First,Transport measurements were used to characterize AlGaN/AlN/GaN/SiC at different temperatures. While the carrier concentration, n=1.32×1013 cm-2, remained relatively unchanged from 300K down to 2 K, the mobility increased from 1672 to 11237 cm2 /Vs.Shubnikov-de Haas oscillations were observed in fields as low as 2.5 T at 2K. Despite the high n, quantum Hall plateaus.Effective-mass values of the 2DEG in the triangular quantum well at the heterointerfaces are obtained by analyzing the temperature-dependent Shubnikov-de Haas（SdH） oscillations. The ratio of the transport lifetime to the quantum scattering time is often evaluated to gain information on the dominant scattering mechanism.This ratio was 9 in our sample, indicating that small-angle scattering is important in this structure.

Related Dissertations

  1. Modeling and Optimization of High Electron Mobility Transistor (HEMT),TN386
  2. Theoretical Calculation and Analysis of Electronic Structure of Single-Walled Carbon Nanotube,TB383.1
  3. Effects of Substrate Pretreatments on the Quality of Gallium Nitride Epilayers,TN304.054
  4. The Measurement and Verification of the Gas-liquid Interfacial Area in Rotating Packed Beds,TQ022
  5. First- principles study of Si and SiC vacancy defect structure and conductivity,TN304
  6. Research on Hole Mobility of Strained-Si/Strained-SiGe,TN432
  7. ZnO thin films and optical properties of heterostructures,O472
  8. AlGaN / GaN HEMT breakdown characteristics and field plate structure optimization design,TN386
  9. The Dressed Bands of Electron in Semiconductor Driven by Laser Field,O471.1
  10. The Optical Properties of Rare Earth in Photonic Crystal and Size-dependence of Ground State Energy of the Excitons in Rare Earth Oxides,O469
  11. Effective mass theory of low-dimensional semiconductor structures,TN303
  12. First-Principles Investigations on the Enhanced Thermoelectric Performance for PbTe under High Pressure,O521.2
  13. Study on Hadron-Quark Phase Transition in the Interior of Hybrid Stars,O572.3
  14. Transport Properties of Thermoelectric Oxide SrTiO3: Theoretical Study,TB34
  15. Extension of the Renormalizable Theory,O413.3
  16. The Characteristic Research of AlGaN/GaN Heterostructure Field Effect Transistors,TN386
  17. Ferroelectric / AlGaN / GaN heterostructure semiconductor interface characterization of thin films,TB383.2
  18. Vibration-Proof Packaging Principle Study of Electronic Product under Random Vibration Excition,TB489
  19. Structure of quantum dots and quantum bit,O413.1
  20. Hard thermal loop approximation of the ideal medium effect model,O412.3
  21. The magnetic field of the neutron star,P145.6

CLC: > Industrial Technology > Radio electronics, telecommunications technology > Semiconductor technology > Field-effect devices
© 2012 www.DissertationTopic.Net  Mobile