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Title: On compensation in Si-doped AlN

Abstract

Controllable n-type doping over wide ranges of carrier concentrations in AlN, or Al-rich AlGaN, is critical to realizing next-generation applications in high-power electronics and deep UV light sources. Silicon is not a hydrogenic donor in AlN as it is in GaN; despite this, the carrier concentration should be controllable, albeit less efficiently, by increasing the donor concentration during growth. At low doping levels, an increase in the Si content leads to a commensurate increase in free electrons. Problematically, this trend does not persist to higher doping levels. In fact, a further increase in the Si concentration leads to a decrease in free electron concentration; this is commonly referred to as the compensation knee. While the nature of this decrease has been attributed to a variety of compensating defects, the mechanism and identity of the predominant defects associated with the knee have not been conclusively determined. Density functional theory calculations using hybrid exchange-correlation functionals have identified VAl+nSiAl complexes as central to mechanistically understanding compensation in the high Si limit in AlN, while secondary impurities and vacancies tend to dominate compensation in the low Si limit. The formation energies and optical signatures of these defects in AlN are calculated and utilized inmore » a grand canonical charge balance solver to identify carrier concentrations as a function of Si content. The results were found to qualitatively reproduce the experimentally observed compensation knee. Furthermore, these calculations predict a shift in the optical emissions present in the high and low doping limits, which is confirmed with detailed photoluminescence measurements.« less

Authors:
 [1];  [1]; ORCiD logo [1];  [1];  [1];  [1]; ORCiD logo [2];  [1];  [1];  [1]
  1. Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA
  2. Adroit Materials, Inc., 2054 Kildaire Farm Rd., Cary, North Carolina 27518, USA
Publication Date:
Research Org.:
Adroit Materials, Cary, NC (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1540172
Alternate Identifier(s):
OSTI ID: 1432412
Grant/Contract Number:  
SC0011883
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 112; Journal Issue: 15; Journal ID: ISSN 0003-6951
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
Physics

Citation Formats

Harris, Joshua S., Baker, Jonathon N., Gaddy, Benjamin E., Bryan, Isaac, Bryan, Zachary, Mirrielees, Kelsey J., Reddy, Pramod, Collazo, Ramón, Sitar, Zlatko, and Irving, Douglas L. On compensation in Si-doped AlN. United States: N. p., 2018. Web. doi:10.1063/1.5022794.
Harris, Joshua S., Baker, Jonathon N., Gaddy, Benjamin E., Bryan, Isaac, Bryan, Zachary, Mirrielees, Kelsey J., Reddy, Pramod, Collazo, Ramón, Sitar, Zlatko, & Irving, Douglas L. On compensation in Si-doped AlN. United States. doi:10.1063/1.5022794.
Harris, Joshua S., Baker, Jonathon N., Gaddy, Benjamin E., Bryan, Isaac, Bryan, Zachary, Mirrielees, Kelsey J., Reddy, Pramod, Collazo, Ramón, Sitar, Zlatko, and Irving, Douglas L. Mon . "On compensation in Si-doped AlN". United States. doi:10.1063/1.5022794. https://www.osti.gov/servlets/purl/1540172.
@article{osti_1540172,
title = {On compensation in Si-doped AlN},
author = {Harris, Joshua S. and Baker, Jonathon N. and Gaddy, Benjamin E. and Bryan, Isaac and Bryan, Zachary and Mirrielees, Kelsey J. and Reddy, Pramod and Collazo, Ramón and Sitar, Zlatko and Irving, Douglas L.},
abstractNote = {Controllable n-type doping over wide ranges of carrier concentrations in AlN, or Al-rich AlGaN, is critical to realizing next-generation applications in high-power electronics and deep UV light sources. Silicon is not a hydrogenic donor in AlN as it is in GaN; despite this, the carrier concentration should be controllable, albeit less efficiently, by increasing the donor concentration during growth. At low doping levels, an increase in the Si content leads to a commensurate increase in free electrons. Problematically, this trend does not persist to higher doping levels. In fact, a further increase in the Si concentration leads to a decrease in free electron concentration; this is commonly referred to as the compensation knee. While the nature of this decrease has been attributed to a variety of compensating defects, the mechanism and identity of the predominant defects associated with the knee have not been conclusively determined. Density functional theory calculations using hybrid exchange-correlation functionals have identified VAl+nSiAl complexes as central to mechanistically understanding compensation in the high Si limit in AlN, while secondary impurities and vacancies tend to dominate compensation in the low Si limit. The formation energies and optical signatures of these defects in AlN are calculated and utilized in a grand canonical charge balance solver to identify carrier concentrations as a function of Si content. The results were found to qualitatively reproduce the experimentally observed compensation knee. Furthermore, these calculations predict a shift in the optical emissions present in the high and low doping limits, which is confirmed with detailed photoluminescence measurements.},
doi = {10.1063/1.5022794},
journal = {Applied Physics Letters},
issn = {0003-6951},
number = 15,
volume = 112,
place = {United States},
year = {2018},
month = {4}
}

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Works referenced in this record:

Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set
journal, July 1996


Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set
journal, October 1996


Ab initio molecular-dynamics simulation of the liquid-metal–amorphous-semiconductor transition in germanium
journal, May 1994


Ab initiomolecular dynamics for liquid metals
journal, January 1993


Lattice Vibration Spectra of Aluminum Nitride
journal, June 1967

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