Enhancement of the second harmonic signal from Hg1−xCdxTe (MCT) in the presence of an anodic oxide film

A.W. Wark, K. McErlean, F.R. Cruickshank, L.E.A. Berlouis, P.F. Brevet

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Second harmonic generation (SHG) is now widely regarded as a valuable tool for investigating electrode surfaces. Typically, most studies have been limited to substrates which lack bulk symmetry and monitoring events such as sub-monolayer formation and surface reconstruction. Here, the development of a model that can be used to quantitatively describe the enhanced SH signal observed in the presence of an anodic oxide film on a non-centrosymmetric substrate, Hg1xCdxTe (MCT), is described. The aim is to further expand the utility of SHG for probing different electrode systems. The growth of the high quality oxide films was first followed by in-situ ellipsometry. For thin films (<100 nm) grown at a constant current density of 150 A cm2, an effectively uniform oxide layer is found with a refractive index n of ~2.15  0.05 and exhibiting no absorption of the incident radiation at 632.8 nm (1.96 eV). In the presence of such an oxide film of 58 nm thickness, the second harmonic (SH) signal intensity measured in reflection is found to be significantly enhanced in both the PIN-POUT and PIN-SOUT polarization configurations. To quantify the changes observed, each layer in the model is assigned its own symmetry and optical constants (at the fundamental,  and harmonic  (= 2) frequencies and a defined thickness. Modeling of the SH rotational anisotropy experiments carried out at different angles of incidence indicated that most of this increase could be accounted for by multiple reflections of the fundamental wave  = 1064 nm (1.17 eV) in the composite ambient/oxide/MCT layer, with little contribution from charge accumulation at the buried MCT/oxide interface for this oxide thickness.
LanguageEnglish
Pages133-141
Number of pages9
JournalJournal of Electroanalytical Chemistry
Volume646
Issue number1-2
DOIs
Publication statusPublished - 15 Jul 2010

Fingerprint

Oxides
Oxide films
Harmonic generation
Electrodes
Surface reconstruction
Optical constants
Ellipsometry
Substrates
Monolayers
Refractive index
Anisotropy
Current density
Polarization
Radiation
Thin films
Monitoring
Composite materials
Experiments

Keywords

  • HgCdTe
  • anodic oxide
  • ellipsometry
  • SHG
  • modeling

Cite this

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title = "Enhancement of the second harmonic signal from Hg1−xCdxTe (MCT) in the presence of an anodic oxide film",
abstract = "Second harmonic generation (SHG) is now widely regarded as a valuable tool for investigating electrode surfaces. Typically, most studies have been limited to substrates which lack bulk symmetry and monitoring events such as sub-monolayer formation and surface reconstruction. Here, the development of a model that can be used to quantitatively describe the enhanced SH signal observed in the presence of an anodic oxide film on a non-centrosymmetric substrate, Hg1xCdxTe (MCT), is described. The aim is to further expand the utility of SHG for probing different electrode systems. The growth of the high quality oxide films was first followed by in-situ ellipsometry. For thin films (<100 nm) grown at a constant current density of 150 A cm2, an effectively uniform oxide layer is found with a refractive index n of ~2.15  0.05 and exhibiting no absorption of the incident radiation at 632.8 nm (1.96 eV). In the presence of such an oxide film of 58 nm thickness, the second harmonic (SH) signal intensity measured in reflection is found to be significantly enhanced in both the PIN-POUT and PIN-SOUT polarization configurations. To quantify the changes observed, each layer in the model is assigned its own symmetry and optical constants (at the fundamental,  and harmonic  (= 2) frequencies and a defined thickness. Modeling of the SH rotational anisotropy experiments carried out at different angles of incidence indicated that most of this increase could be accounted for by multiple reflections of the fundamental wave  = 1064 nm (1.17 eV) in the composite ambient/oxide/MCT layer, with little contribution from charge accumulation at the buried MCT/oxide interface for this oxide thickness.",
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Enhancement of the second harmonic signal from Hg1−xCdxTe (MCT) in the presence of an anodic oxide film. / Wark, A.W.; McErlean, K.; Cruickshank, F.R.; Berlouis, L.E.A.; Brevet, P.F.

In: Journal of Electroanalytical Chemistry, Vol. 646, No. 1-2, 15.07.2010, p. 133-141.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Enhancement of the second harmonic signal from Hg1−xCdxTe (MCT) in the presence of an anodic oxide film

AU - Wark, A.W.

AU - McErlean, K.

AU - Cruickshank, F.R.

AU - Berlouis, L.E.A.

AU - Brevet, P.F.

PY - 2010/7/15

Y1 - 2010/7/15

N2 - Second harmonic generation (SHG) is now widely regarded as a valuable tool for investigating electrode surfaces. Typically, most studies have been limited to substrates which lack bulk symmetry and monitoring events such as sub-monolayer formation and surface reconstruction. Here, the development of a model that can be used to quantitatively describe the enhanced SH signal observed in the presence of an anodic oxide film on a non-centrosymmetric substrate, Hg1xCdxTe (MCT), is described. The aim is to further expand the utility of SHG for probing different electrode systems. The growth of the high quality oxide films was first followed by in-situ ellipsometry. For thin films (<100 nm) grown at a constant current density of 150 A cm2, an effectively uniform oxide layer is found with a refractive index n of ~2.15  0.05 and exhibiting no absorption of the incident radiation at 632.8 nm (1.96 eV). In the presence of such an oxide film of 58 nm thickness, the second harmonic (SH) signal intensity measured in reflection is found to be significantly enhanced in both the PIN-POUT and PIN-SOUT polarization configurations. To quantify the changes observed, each layer in the model is assigned its own symmetry and optical constants (at the fundamental,  and harmonic  (= 2) frequencies and a defined thickness. Modeling of the SH rotational anisotropy experiments carried out at different angles of incidence indicated that most of this increase could be accounted for by multiple reflections of the fundamental wave  = 1064 nm (1.17 eV) in the composite ambient/oxide/MCT layer, with little contribution from charge accumulation at the buried MCT/oxide interface for this oxide thickness.

AB - Second harmonic generation (SHG) is now widely regarded as a valuable tool for investigating electrode surfaces. Typically, most studies have been limited to substrates which lack bulk symmetry and monitoring events such as sub-monolayer formation and surface reconstruction. Here, the development of a model that can be used to quantitatively describe the enhanced SH signal observed in the presence of an anodic oxide film on a non-centrosymmetric substrate, Hg1xCdxTe (MCT), is described. The aim is to further expand the utility of SHG for probing different electrode systems. The growth of the high quality oxide films was first followed by in-situ ellipsometry. For thin films (<100 nm) grown at a constant current density of 150 A cm2, an effectively uniform oxide layer is found with a refractive index n of ~2.15  0.05 and exhibiting no absorption of the incident radiation at 632.8 nm (1.96 eV). In the presence of such an oxide film of 58 nm thickness, the second harmonic (SH) signal intensity measured in reflection is found to be significantly enhanced in both the PIN-POUT and PIN-SOUT polarization configurations. To quantify the changes observed, each layer in the model is assigned its own symmetry and optical constants (at the fundamental,  and harmonic  (= 2) frequencies and a defined thickness. Modeling of the SH rotational anisotropy experiments carried out at different angles of incidence indicated that most of this increase could be accounted for by multiple reflections of the fundamental wave  = 1064 nm (1.17 eV) in the composite ambient/oxide/MCT layer, with little contribution from charge accumulation at the buried MCT/oxide interface for this oxide thickness.

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KW - anodic oxide

KW - ellipsometry

KW - SHG

KW - modeling

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EP - 141

JO - Journal of Electroanalytical Chemistry

T2 - Journal of Electroanalytical Chemistry

JF - Journal of Electroanalytical Chemistry

SN - 0022-0728

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