Nonequilibrium-Plasma-Synthesized ZnO Nanocrystals with Plasmon Resonance Tunable via Al Doping and Quantum Confinement

Benjamin L. Greenberg, Shreyashi Ganguly, Jacob T. Held, Nicolaas J. Kramer, K. Andre Mkhoyan, Eray Aydil, Uwe R. Kortshagen

Research output: Contribution to journalArticle

Abstract

Metal oxide semiconductor nanocrystals (NCs) exhibit localized surface plasmon resonances (LSPRs) tunable within the infrared (IR) region of the electromagnetic spectrum by vacancy or impurity doping. Although a variety of these NCs have been produced using colloidal synthesis methods, incorporation and activation of dopants in the liquid phase has often been challenging. Herein, using Al-doped ZnO (AZO) NCs as an example, we demonstrate the potential of nonthermal plasma synthesis as an alternative strategy for the production of doped metal oxide NCs. Exploiting unique, thoroughly nonequilibrium synthesis conditions, we obtain NCs in which dopants are not segregated to the NC surfaces and local doping levels are high near the NC centers. Thus, we achieve overall doping levels as high as 2 × 1020 cm-3 in NCs with diameters ranging from 12.6 to 3.6 nm, and for the first time experimentally demonstrate a clear quantum confinement blue shift of the LSPR energy in vacancy- and impurity-doped semiconductor NCs. We propose that doping of central cores and heavy doping of small NCs are achievable via nonthermal plasma synthesis, because chemical potential differences between dopant and host atoms - which hinder dopant incorporation in colloidal synthesis - are irrelevant when NC nucleation and growth proceed via irreversible interactions among highly reactive gas-phase ions and radicals and ligand-free NC surfaces. We explore how the distinctive nucleation and growth kinetics occurring in the plasma influences dopant distribution and activation, defect structure, and impurity phase formation.

Original languageEnglish (US)
Pages (from-to)8162-8169
Number of pages8
JournalNano Letters
Volume15
Issue number12
DOIs
StatePublished - Dec 9 2015

Fingerprint

nonequilibrium plasmas
Quantum confinement
Nanocrystals
nanocrystals
Doping (additives)
Plasmas
synthesis
Surface plasmon resonance
Impurities
surface plasmon resonance
impurities
Vacancies
Nucleation
Metals
Chemical activation
nucleation
activation
electromagnetic spectra
Defect structures
Chemical potential

Keywords

  • aluminum-doped zinc oxide
  • doping
  • nanocrystals
  • plasma
  • plasmonics
  • quantum confinement

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

Cite this

Greenberg, B. L., Ganguly, S., Held, J. T., Kramer, N. J., Mkhoyan, K. A., Aydil, E., & Kortshagen, U. R. (2015). Nonequilibrium-Plasma-Synthesized ZnO Nanocrystals with Plasmon Resonance Tunable via Al Doping and Quantum Confinement. Nano Letters, 15(12), 8162-8169. https://doi.org/10.1021/acs.nanolett.5b03600

Nonequilibrium-Plasma-Synthesized ZnO Nanocrystals with Plasmon Resonance Tunable via Al Doping and Quantum Confinement. / Greenberg, Benjamin L.; Ganguly, Shreyashi; Held, Jacob T.; Kramer, Nicolaas J.; Mkhoyan, K. Andre; Aydil, Eray; Kortshagen, Uwe R.

In: Nano Letters, Vol. 15, No. 12, 09.12.2015, p. 8162-8169.

Research output: Contribution to journalArticle

Greenberg, Benjamin L. ; Ganguly, Shreyashi ; Held, Jacob T. ; Kramer, Nicolaas J. ; Mkhoyan, K. Andre ; Aydil, Eray ; Kortshagen, Uwe R. / Nonequilibrium-Plasma-Synthesized ZnO Nanocrystals with Plasmon Resonance Tunable via Al Doping and Quantum Confinement. In: Nano Letters. 2015 ; Vol. 15, No. 12. pp. 8162-8169.
@article{d032a9991d6a4469aac79188000f8f58,
title = "Nonequilibrium-Plasma-Synthesized ZnO Nanocrystals with Plasmon Resonance Tunable via Al Doping and Quantum Confinement",
abstract = "Metal oxide semiconductor nanocrystals (NCs) exhibit localized surface plasmon resonances (LSPRs) tunable within the infrared (IR) region of the electromagnetic spectrum by vacancy or impurity doping. Although a variety of these NCs have been produced using colloidal synthesis methods, incorporation and activation of dopants in the liquid phase has often been challenging. Herein, using Al-doped ZnO (AZO) NCs as an example, we demonstrate the potential of nonthermal plasma synthesis as an alternative strategy for the production of doped metal oxide NCs. Exploiting unique, thoroughly nonequilibrium synthesis conditions, we obtain NCs in which dopants are not segregated to the NC surfaces and local doping levels are high near the NC centers. Thus, we achieve overall doping levels as high as 2 × 1020 cm-3 in NCs with diameters ranging from 12.6 to 3.6 nm, and for the first time experimentally demonstrate a clear quantum confinement blue shift of the LSPR energy in vacancy- and impurity-doped semiconductor NCs. We propose that doping of central cores and heavy doping of small NCs are achievable via nonthermal plasma synthesis, because chemical potential differences between dopant and host atoms - which hinder dopant incorporation in colloidal synthesis - are irrelevant when NC nucleation and growth proceed via irreversible interactions among highly reactive gas-phase ions and radicals and ligand-free NC surfaces. We explore how the distinctive nucleation and growth kinetics occurring in the plasma influences dopant distribution and activation, defect structure, and impurity phase formation.",
keywords = "aluminum-doped zinc oxide, doping, nanocrystals, plasma, plasmonics, quantum confinement",
author = "Greenberg, {Benjamin L.} and Shreyashi Ganguly and Held, {Jacob T.} and Kramer, {Nicolaas J.} and Mkhoyan, {K. Andre} and Eray Aydil and Kortshagen, {Uwe R.}",
year = "2015",
month = "12",
day = "9",
doi = "10.1021/acs.nanolett.5b03600",
language = "English (US)",
volume = "15",
pages = "8162--8169",
journal = "Nano Letters",
issn = "1530-6984",
publisher = "American Chemical Society",
number = "12",

}

TY - JOUR

T1 - Nonequilibrium-Plasma-Synthesized ZnO Nanocrystals with Plasmon Resonance Tunable via Al Doping and Quantum Confinement

AU - Greenberg, Benjamin L.

AU - Ganguly, Shreyashi

AU - Held, Jacob T.

AU - Kramer, Nicolaas J.

AU - Mkhoyan, K. Andre

AU - Aydil, Eray

AU - Kortshagen, Uwe R.

PY - 2015/12/9

Y1 - 2015/12/9

N2 - Metal oxide semiconductor nanocrystals (NCs) exhibit localized surface plasmon resonances (LSPRs) tunable within the infrared (IR) region of the electromagnetic spectrum by vacancy or impurity doping. Although a variety of these NCs have been produced using colloidal synthesis methods, incorporation and activation of dopants in the liquid phase has often been challenging. Herein, using Al-doped ZnO (AZO) NCs as an example, we demonstrate the potential of nonthermal plasma synthesis as an alternative strategy for the production of doped metal oxide NCs. Exploiting unique, thoroughly nonequilibrium synthesis conditions, we obtain NCs in which dopants are not segregated to the NC surfaces and local doping levels are high near the NC centers. Thus, we achieve overall doping levels as high as 2 × 1020 cm-3 in NCs with diameters ranging from 12.6 to 3.6 nm, and for the first time experimentally demonstrate a clear quantum confinement blue shift of the LSPR energy in vacancy- and impurity-doped semiconductor NCs. We propose that doping of central cores and heavy doping of small NCs are achievable via nonthermal plasma synthesis, because chemical potential differences between dopant and host atoms - which hinder dopant incorporation in colloidal synthesis - are irrelevant when NC nucleation and growth proceed via irreversible interactions among highly reactive gas-phase ions and radicals and ligand-free NC surfaces. We explore how the distinctive nucleation and growth kinetics occurring in the plasma influences dopant distribution and activation, defect structure, and impurity phase formation.

AB - Metal oxide semiconductor nanocrystals (NCs) exhibit localized surface plasmon resonances (LSPRs) tunable within the infrared (IR) region of the electromagnetic spectrum by vacancy or impurity doping. Although a variety of these NCs have been produced using colloidal synthesis methods, incorporation and activation of dopants in the liquid phase has often been challenging. Herein, using Al-doped ZnO (AZO) NCs as an example, we demonstrate the potential of nonthermal plasma synthesis as an alternative strategy for the production of doped metal oxide NCs. Exploiting unique, thoroughly nonequilibrium synthesis conditions, we obtain NCs in which dopants are not segregated to the NC surfaces and local doping levels are high near the NC centers. Thus, we achieve overall doping levels as high as 2 × 1020 cm-3 in NCs with diameters ranging from 12.6 to 3.6 nm, and for the first time experimentally demonstrate a clear quantum confinement blue shift of the LSPR energy in vacancy- and impurity-doped semiconductor NCs. We propose that doping of central cores and heavy doping of small NCs are achievable via nonthermal plasma synthesis, because chemical potential differences between dopant and host atoms - which hinder dopant incorporation in colloidal synthesis - are irrelevant when NC nucleation and growth proceed via irreversible interactions among highly reactive gas-phase ions and radicals and ligand-free NC surfaces. We explore how the distinctive nucleation and growth kinetics occurring in the plasma influences dopant distribution and activation, defect structure, and impurity phase formation.

KW - aluminum-doped zinc oxide

KW - doping

KW - nanocrystals

KW - plasma

KW - plasmonics

KW - quantum confinement

UR - http://www.scopus.com/inward/record.url?scp=84949657409&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84949657409&partnerID=8YFLogxK

U2 - 10.1021/acs.nanolett.5b03600

DO - 10.1021/acs.nanolett.5b03600

M3 - Article

VL - 15

SP - 8162

EP - 8169

JO - Nano Letters

JF - Nano Letters

SN - 1530-6984

IS - 12

ER -