Atomistic description of wave function localization effects in InxGa1-xN alloys and quantum wells

S. Schulz; O. Marquardt; C. Coughlan; M. A. Caro; O. Brandt; E. P. O'Reilly

doi:10.1117/12.2084800

Atomistic description of wave function localization effects in In_xGa_1-xN alloys and quantum wells

S. Schulz
, O. Marquardt
, C. Coughlan
, M. A. Caro
, O. Brandt
, E. P. O'Reilly

Research output: Chapter in Book/Report/Conference proceedings › Chapter › peer-review

Abstract

We present a detailed analysis of wave function localization effects in In_xGa_1-xN alloys and quantum wells. Our work is based on density functional theory to analyze the impact of isolated and clustered In atoms on the wave function localization characteristics in In_xGa_1-xN alloys. We address the electronic structure of In0.25Ga0.25N/GaN quantum wells by means of an atomistic tight-binding model. Random alloy fluctuations in the quantum well region and well-width fluctuations are explicitly taken into account. The tight-binding model includes strain and built-in field fluctuations arising from the random In distribution. Our density functional theory study reveals increasing hole wave function localization effects when an increasing number of In atoms share the same N atom. We find that these effects are less pronounced for the electrons. Our tight-binding analysis of In0.25Ga0.75N/GaN quantum wells also reflects this behavior, revealing strong hole localization effects arising from the random In atom distribution. We also show that the excited hole states are strongly localized over an energy range of approximately 50 meV from the top of the valence band. For the quantum wells considered here we observe that well-width fluctuations lead to electron wave function localization effects.

Original language	English
Title of host publication	Physics and Simulation of Optoelectronic Devices XXIII
Editors	Bernd Witzigmann, Yasuhiko Arakawa, Fritz Henneberger, Marek Osinski
Publisher	SPIE
ISBN (Electronic)	9781628414479
DOIs	https://doi.org/10.1117/12.2084800
Publication status	Published - 2015
Event	23rd SPIE Conference on Physics and Simulation of Optoelectronic Devices - San Francisco, United States Duration: 9 Feb 2015 → 12 Feb 2015

Publication series

Name	Proceedings of SPIE - The International Society for Optical Engineering
Volume	9357
ISSN (Print)	0277-786X
ISSN (Electronic)	1996-756X

Conference

Conference	23rd SPIE Conference on Physics and Simulation of Optoelectronic Devices
Country/Territory	United States
City	San Francisco
Period	9/02/15 → 12/02/15

Keywords

alloy fluctuations
density functional theory
electronic structure
InGaN
Nitrides
quantum wells

Access to Document

10.1117/12.2084800

Cite this

Schulz, S., Marquardt, O., Coughlan, C., Caro, M. A., Brandt, O., & O'Reilly, E. P. (2015). Atomistic description of wave function localization effects in In_xGa_1-xN alloys and quantum wells. In B. Witzigmann, Y. Arakawa, F. Henneberger, & M. Osinski (Eds.), Physics and Simulation of Optoelectronic Devices XXIII Article 93570C (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 9357). SPIE. https://doi.org/10.1117/12.2084800

Schulz, S. ; Marquardt, O. ; Coughlan, C. et al. / Atomistic description of wave function localization effects in In_xGa_1-xN alloys and quantum wells. Physics and Simulation of Optoelectronic Devices XXIII. editor / Bernd Witzigmann ; Yasuhiko Arakawa ; Fritz Henneberger ; Marek Osinski. SPIE, 2015. (Proceedings of SPIE - The International Society for Optical Engineering).

@inbook{ebb50d04cc7b4ebe9d127e50ff8a72c7,

title = "Atomistic description of wave function localization effects in InxGa1-xN alloys and quantum wells",

abstract = "We present a detailed analysis of wave function localization effects in InxGa1-xN alloys and quantum wells. Our work is based on density functional theory to analyze the impact of isolated and clustered In atoms on the wave function localization characteristics in InxGa1-xN alloys. We address the electronic structure of In0.25Ga0.25N/GaN quantum wells by means of an atomistic tight-binding model. Random alloy fluctuations in the quantum well region and well-width fluctuations are explicitly taken into account. The tight-binding model includes strain and built-in field fluctuations arising from the random In distribution. Our density functional theory study reveals increasing hole wave function localization effects when an increasing number of In atoms share the same N atom. We find that these effects are less pronounced for the electrons. Our tight-binding analysis of In0.25Ga0.75N/GaN quantum wells also reflects this behavior, revealing strong hole localization effects arising from the random In atom distribution. We also show that the excited hole states are strongly localized over an energy range of approximately 50 meV from the top of the valence band. For the quantum wells considered here we observe that well-width fluctuations lead to electron wave function localization effects.",

keywords = "alloy fluctuations, density functional theory, electronic structure, InGaN, Nitrides, quantum wells",

author = "S. Schulz and O. Marquardt and C. Coughlan and Caro, \{M. A.\} and O. Brandt and O'Reilly, \{E. P.\}",

note = "Publisher Copyright: {\textcopyright} 2015 SPIE.; 23rd SPIE Conference on Physics and Simulation of Optoelectronic Devices ; Conference date: 09-02-2015 Through 12-02-2015",

year = "2015",

doi = "10.1117/12.2084800",

language = "English",

series = "Proceedings of SPIE - The International Society for Optical Engineering",

publisher = "SPIE",

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Schulz, S, Marquardt, O, Coughlan, C, Caro, MA, Brandt, O & O'Reilly, EP 2015, Atomistic description of wave function localization effects in In_xGa_1-xN alloys and quantum wells. in B Witzigmann, Y Arakawa, F Henneberger & M Osinski (eds), Physics and Simulation of Optoelectronic Devices XXIII., 93570C, Proceedings of SPIE - The International Society for Optical Engineering, vol. 9357, SPIE, 23rd SPIE Conference on Physics and Simulation of Optoelectronic Devices, San Francisco, United States, 9/02/15. https://doi.org/10.1117/12.2084800

Atomistic description of wave function localization effects in In_xGa_1-xN alloys and quantum wells. / Schulz, S.; Marquardt, O.; Coughlan, C. et al.
Physics and Simulation of Optoelectronic Devices XXIII. ed. / Bernd Witzigmann; Yasuhiko Arakawa; Fritz Henneberger; Marek Osinski. SPIE, 2015. 93570C (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 9357).

Research output: Chapter in Book/Report/Conference proceedings › Chapter › peer-review

TY - CHAP

T1 - Atomistic description of wave function localization effects in InxGa1-xN alloys and quantum wells

AU - Schulz, S.

AU - Marquardt, O.

AU - Coughlan, C.

AU - Caro, M. A.

AU - Brandt, O.

AU - O'Reilly, E. P.

PY - 2015

Y1 - 2015

N2 - We present a detailed analysis of wave function localization effects in InxGa1-xN alloys and quantum wells. Our work is based on density functional theory to analyze the impact of isolated and clustered In atoms on the wave function localization characteristics in InxGa1-xN alloys. We address the electronic structure of In0.25Ga0.25N/GaN quantum wells by means of an atomistic tight-binding model. Random alloy fluctuations in the quantum well region and well-width fluctuations are explicitly taken into account. The tight-binding model includes strain and built-in field fluctuations arising from the random In distribution. Our density functional theory study reveals increasing hole wave function localization effects when an increasing number of In atoms share the same N atom. We find that these effects are less pronounced for the electrons. Our tight-binding analysis of In0.25Ga0.75N/GaN quantum wells also reflects this behavior, revealing strong hole localization effects arising from the random In atom distribution. We also show that the excited hole states are strongly localized over an energy range of approximately 50 meV from the top of the valence band. For the quantum wells considered here we observe that well-width fluctuations lead to electron wave function localization effects.

AB - We present a detailed analysis of wave function localization effects in InxGa1-xN alloys and quantum wells. Our work is based on density functional theory to analyze the impact of isolated and clustered In atoms on the wave function localization characteristics in InxGa1-xN alloys. We address the electronic structure of In0.25Ga0.25N/GaN quantum wells by means of an atomistic tight-binding model. Random alloy fluctuations in the quantum well region and well-width fluctuations are explicitly taken into account. The tight-binding model includes strain and built-in field fluctuations arising from the random In distribution. Our density functional theory study reveals increasing hole wave function localization effects when an increasing number of In atoms share the same N atom. We find that these effects are less pronounced for the electrons. Our tight-binding analysis of In0.25Ga0.75N/GaN quantum wells also reflects this behavior, revealing strong hole localization effects arising from the random In atom distribution. We also show that the excited hole states are strongly localized over an energy range of approximately 50 meV from the top of the valence band. For the quantum wells considered here we observe that well-width fluctuations lead to electron wave function localization effects.

KW - alloy fluctuations

KW - density functional theory

KW - electronic structure

KW - InGaN

KW - Nitrides

KW - quantum wells

UR - https://www.scopus.com/pages/publications/84947756193

U2 - 10.1117/12.2084800

DO - 10.1117/12.2084800

M3 - Chapter

AN - SCOPUS:84947756193

T3 - Proceedings of SPIE - The International Society for Optical Engineering

BT - Physics and Simulation of Optoelectronic Devices XXIII

A2 - Witzigmann, Bernd

A2 - Arakawa, Yasuhiko

A2 - Henneberger, Fritz

A2 - Osinski, Marek

PB - SPIE

T2 - 23rd SPIE Conference on Physics and Simulation of Optoelectronic Devices

Y2 - 9 February 2015 through 12 February 2015

ER -

Schulz S, Marquardt O, Coughlan C, Caro MA, Brandt O, O'Reilly EP. Atomistic description of wave function localization effects in In_xGa_1-xN alloys and quantum wells. In Witzigmann B, Arakawa Y, Henneberger F, Osinski M, editors, Physics and Simulation of Optoelectronic Devices XXIII. SPIE. 2015. 93570C. (Proceedings of SPIE - The International Society for Optical Engineering). doi: 10.1117/12.2084800