Crystallographic Characterisation of Ultra-Thin, or Amorphous Transparent Conducting Oxides—The Case for Raman Spectroscopy

Caffrey, David; Zhussupbekova, Ainur; Vijayaraghavan, Rajani K.; Ainabаyev, Ardak; Kaisha, Aitkazy; Sugurbekova, Gulnar; Shvets, I. V.; Fleischer, K.

doi:10.3390/ma13020267

Cited by 10 publications

(10 citation statements)

References 58 publications

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“…11,13 Conductivity variations were instead driven by large variations in the mobility. Best samples show high mobilities with a maxima of 9-10 cm 2 /Vs being observed for a wide range of film compositions, but this is a noticeable reduction from literature best values of >16 cm 2 /Vs, 13,32,35 which are achieved without special treatments.…”

Section: Resultsmentioning

confidence: 78%

Low-Cost, High-Performance Spray Pyrolysis-Grown Amorphous Zinc Tin Oxide: The Challenge of a Complex Growth Process

Zhussupbekova

Caffrey

Zhussupbekov

et al. 2020

ACS Appl. Mater. Interfaces

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Transparent conductive oxides (TCOs) are important materials for a wide range of optoelectronic devices. Amorphous zinc-tin oxide (a-ZTO) is a TCO and one of the best non toxic, low-cost replacement for more expensive amorphous indium-gallium-zinc oxide. Here, we employ spray pyrolysis, an inexpensive and versatile chemical vapour deposition based technique, to synthesise a-ZTO with an as-deposited conductivity of ≈300 S/cm -the highest value hitherto among the reported solution processed films. Compositional analysis via X-ray photoelectron spectroscopy reveals a non-stoichimoetric transfer of Zn and Sn from the dissolved precursors into the film, with best electrical properties achieved at a film composition of x film =0.38±0.04 ((ZnO) x (SnO 2 ) 1 −x (0

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Section: Resultsmentioning

confidence: 78%

Low-Cost, High-Performance Spray Pyrolysis-Grown Amorphous Zinc Tin Oxide: The Challenge of a Complex Growth Process

Zhussupbekova

Caffrey

Zhussupbekov

et al. 2020

ACS Appl. Mater. Interfaces

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“…1a, b. Raman spectroscopy was also used to provide information on the quality of the material synthesized, as shown in Supplementary Fig. 1c 39 . XRD allowed the crystallinity of the PtTe 2 film to be examined (see Supplementary Fig.…”

Section: Resultsmentioning

confidence: 99%

Imaging and identification of point defects in PtTe2

et al. 2021

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The properties and performance of two-dimensional (2D) materials can be greatly affected by point defects. PtTe2, a 2D material that belongs to the group 10 transition metal dichalcogenides, is a type-II Dirac semimetal, which has gained a lot of attention recently due to its potential for applications in catalysis, photonics, and spintronics. Here, we provide an experimental and theoretical investigation of point defects on and near the surface of PtTe2. Using scanning tunneling microscopy and scanning tunneling spectroscopy (STS) measurements, in combination with first-principle calculations, we identify and characterize five common surface and subsurface point defects. The influence of these defects on the electronic structure of PtTe2 is explored in detail through grid STS measurements and complementary density functional theory calculations. We believe these findings will be of significance to future efforts to engineer point defects in PtTe2, which is an interesting and enticing approach to tune the charge-carrier mobility and electron–hole recombination rates, as well as the site reactivity for catalysis.

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“…It remains thereby difficult to distinguish a priori from which thickness one can rely on the extracted signal. Furthermore, the subtraction of the dominant substrate signal is vulnerable to the acquisition noise and the choice of the baseline subtraction [50]. This is particularly important in the present work as the silica films have very weak Raman intensities (due to the low cross-section of the silica film and its small thickness) that are already dominated by noise and that overlap with the likewise broad signal of the glass substrate.…”

Section: Optimizing the Extraction Of The Raman Signal Signature Of The Sputtered Silica Filmmentioning

confidence: 99%

“…In this case, it is highly challenging to obtain an accurate Raman spectra of the layer due to the similarity between the two Raman signals. This makes the subtraction of the substrate background difficult and leads to inconsistent or inaccurate results [50]. In consequence, the number of Raman structural investigations on amorphous silica thin film (<1 µm), that has additionally a low Raman cross-section [51], is very limited [52].…”

Section: Introductionmentioning

confidence: 99%

Structural analysis of sputtered amorphous silica thin films: A Raman spectroscopy investigation

et al. 2021

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In this work, a structural characterization of sputtered silica films was carried out using Raman spectroscopy. Due to the low cross-section and the thinness of the silica layer, its Raman signature is dwarfed by that of the glass substrate and is therefore difficult to extract.Overcoming these limitations represents an experimental challenge and requires the development of specific analysis strategies. For this purpose, an integrated approach for extracting and interpreting the Raman signature of amorphous silica films deposited on a soda-lime glass substrate was developed, based on three distinct methods: delamination of the sputtered silica film, creating a reflective mask substrate by depositing a metallic silver coating on the glass substrate and applying a numerical signal analysis (Non-negative matrix factorization) to the multidimensional dataset acquired through depth profile acquisitions on silica films directly deposited on a glass substrate. The reliability of each proposed method is demonstrated for the extraction of the silica thin film Raman spectra. These various methods can be easily extended to other materials, either crystalline or amorphous. Furthermore, we discuss the advantages and the limits of each approach.Applying this methodology allowed us to highlight the structural differences between sputtered silica thin film and bulk vitreous silica glass (v-SiO2). Magnetron sputtering film deposition is shown to form dense silica glass layers, with an estimated densification ratio, 2 measured by x-ray reflectivity, equal to 7%. At the medium distance range, the network connectivity change in v-SiO2 is expressed by an unusually high population of three-membered rings leading to a more compact structure. The short-range order transformation was also studied by deriving the intertetrahedral angle decrease. The present results could be a step towards advanced investigation to gain insights into the structure of films at the atomic level.

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Crystallographic Characterisation of Ultra-Thin, or Amorphous Transparent Conducting Oxides—The Case for Raman Spectroscopy

Cited by 10 publications

References 58 publications

Low-Cost, High-Performance Spray Pyrolysis-Grown Amorphous Zinc Tin Oxide: The Challenge of a Complex Growth Process

Low-Cost, High-Performance Spray Pyrolysis-Grown Amorphous Zinc Tin Oxide: The Challenge of a Complex Growth Process

Imaging and identification of point defects in PtTe2

Structural analysis of sputtered amorphous silica thin films: A Raman spectroscopy investigation

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