In-situ evaluation of the anodic oxide growth on Hg1−xCdxTe (MCT) using ellipsometry and second harmonic generation

Wark, Alastair W.; Berlouis, L.E.A.; Cruickshank, F. R.; Pugh, D.; Brevet, Pierre‐François

doi:10.1007/s11664-000-0199-9

Cited by 2 publications

(2 citation statements)

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“…As can be seen from the figure, the model used provides an excellent fit to the experimental data. The initial oxide layer grown in this medium had a refractive index of 2.1 and this is consistent with data from the literatures [27,46]. The layer here consisted of essentially CdTeO 3 and HgTeO 3 [39].…”

Section: Anodic Oxide Growthsupporting

confidence: 89%

“…Whereas the MCT has a zinc-blende structure similar to that of GaAs, the anodic oxide consists of a mixture of CdTeO 3 , HgTeO 3 and TeO 2 and is thus essentially centrosymmetic. Previous measurements on an oxidecovered MCT sample revealed that in the presence of the oxide film, the SH intensity was substantially increased over that of the bare MCT surface [27]. This observation suggests that SH generation within the MCT, at the MCT/oxide film and at film/air interfaces have all got to be carefully accounted for in order to quantify the various contributions to the observed SH signal from the oxide-covered MCT surface.…”

Section: Introductionmentioning

confidence: 96%

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

Wark

McErlean

Cruickshank

et al. 2010

Journal of Electroanalytical Chemistry

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a b s t r a c tSecond 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, Hg 1Àx Cd x Te (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 lA cm À2 , 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 P IN -P OUT and P IN -S OUT polarisation configurations. To quantify the changes observed, each layer in the model is assigned its own symmetry and optical constants at the fundamental, x and harmonic X (= 2x) 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 x = 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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Section: Anodic Oxide Growthsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 96%