Polarization-Engineered III-V Nitride Heterostructure Devices by Molecular Beam Epitaxy

Doctoral Dissertation

Abstract

III-V nitride semiconductors have attracted a lot of interest for their applications in optoelectronic and high power devices. However the highly resistive p-type layers of nitrides have limited the performance of bipolar devices. Polarization charges present in nitride heterojunctions can be engineered to enhance the performance of different devices and introduce novel material physics not present in other semiconductors.

Regions of 2- and 3-dimensional mobile carriers can be produced with the aid of polarization charges in graded AlGaN structures. Such impurity-free electron concentrations have been demonstrated experimentally. Polarization-enhanced hole concentrations are theoretically and experimentally studied in this work. Bandgap engineering of polarization-induced doping in III-V nitrides is demonstrated by Molecular Beam Epitaxy. Applications of these polarization-enhanced layers in working p-n junction diodes is achieved.

Polarization charges can also utilized to enhanced the properties of other devices. p-type conductivity in AlN/GaN superlattice structures is increased due to field-assisted acceptor ionization. Improved p-type conductivity as compared to conventional bulk doped GaN structures is achieved, and insertion into a p-n junction allows vertical conductivity.

Demonstration of the nitride-based backward diodes is also achieved by utilizing the high polarization-induced electric fields. Interband tunneling current is observed in GaN-AlN-GaN p-n junctions under reverse bias. Application of these backward diodes as a zero bias RF detector is demonstrated.

Attributes

Attribute NameValues
URN
  • etd-04162009-162805

Author John David Simon
Advisor Debdeep Jena
Contributor Debdeep Jena, Committee Chair
Contributor Patrick Fay, Committee Member
Contributor Gregory Snider, Committee Member
Contributor Huili Xing, Committee Member
Degree Level Doctoral Dissertation
Degree Discipline Electrical Engineering
Degree Name PhD
Defense Date
  • 2009-04-09

Submission Date 2009-04-16
Country
  • United States of America

Subject
  • Doping

  • GaN

  • Polarization

  • p-type

Publisher
  • University of Notre Dame

Language
  • English

Record Visibility and Access Public
Content License
  • All rights reserved

Departments and Units

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