Abstract

In this work, a new strategy for achieving efficient p-type doping in high bandgap nitride semiconductors to overcome the fundamental issue of high activation energy has been proposed and investigated theoretically and demonstrated experimentally. Specifically, in an Al x Ga 1-x N/GaN superlattice structure, by modulation doping of Mg in the Al x Ga 1-x N barriers, high concentration of holes is generated throughout the material. A hole concentration as high as 1.1 x 10 18 cm -3 has been achieved, which is about one order of magnitude higher than that typically achievable by direct doping GaN. Results from first-principal calculations indicate that the coupling and hybridization between Mg 2p impurity and the host N 2p orbitals are main reasons for the generation of resonant states in the GaN wells, which further results in the high hole concentration. We expect this approach to be equally applicable for other high bandgap materials where efficient p-type doing is difficult. Furthermore, a two-carrier-species Hall-effect model is proposed to delineate and discriminate the characteristics of the bulk and 2D hole, which usually coexist in superlattice-like doping systems. The model reported here can also be used to explain the abnormal freeze-in effect observed in many previous reports.

Department(s)

Electrical and Computer Engineering

Publication Status

Open Access

Comments

National Science Foundation, Grant 2013AA03A101

International Standard Serial Number (ISSN)

2045-2322

Document Type

Article - Journal

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 2024 The Authors, All rights reserved.

Creative Commons Licensing

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

Publication Date

18 Jan 2016

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