
READ ME File For 'BeSbTe stoichiometric engineering dataset'

Dataset DOI: 10.5258/SOTON/D0799


This dataset supports the publication:
D. Piccinotti, B. Gholipour, J. Yao, K. F. MacDonald, B. E. Hayden, & N. I. Zheludev (2019). 
Stoichiometric Engineering of Chalcogenide Semiconductor Alloys for Nanophotonic Applications. 
in Advanced Materials 


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This research data description should be read and understood in the context of the corresponding manuscript. The figure numbers correspond to the figure numbers of the manuscript and the data corresponds to the data as shown in the figures.


The figure descriptions as given in the corresponding manuscript are given below.  

The file contains the data for figures 1, 2b&c, and 3-6.
[Figure 1a is a schematic diagram only]


Figure 1: Permittivity of BST alloys. Spectral dispersion of the real part ε’ of relative permittivity for a representative selection of binary and ternary Bi:Sb:Te chalcogenides (as labelled).

Figure 2: Combinatorial synthesis of chalcogenide semiconductor thin films. (a) Schematic of the apparatus for physical vapour deposition of ternary compositional gradient thin BST films, illustrating only the configuration of the most essential components of the ultra-high vacuum system - namely the computer-controlled [K-cell] evaporation sources for each constituent element, ‘wedge shutters’ [which control the density gradient of each element over the substrate], and the target substrate. b) Compositional ternary plot showing the stoichiometric range encompassed in the present study – each green point denotes the measured elemental ratio at one of the compositional gradient sampling points. (c) Distributions of Bi, Sb and Te over the surface of a representative BST compositional gradient sample, evaluated by energy dispersive x-ray spectroscopy.

Figure 3: Compositional variation of BST optical properties. Spectral dispersion of (a) refractive index n, (b) extinction coefficient κ, and (c, d) the real and imaginary parts ε’ and ε’’ respectively of relative permittivity for a selection of BST alloy compositions [as labelled], measured by variable-angle spectroscopic ellipsometry. Insets to (a) and (b) show detail in the 200-400 nm wavelength range. The inset to (c) shows the stoichiometric range encompassed in the present study as in Figure 2b, with black, red, magenta and blue dots denoting the compositions for which spectra are plotted using lines of the same colour, in the panels of this figure.

Figure 4: ε’ = 0 properties of BST. (a) VIS to NIR ε’ = 0 wavelength λ2, below which an alloy is plasmonic [i.e. has a negative value of ε’] as a function of composition, and (b) the corresponding value of ε’’. (c) Compositional dependence of the value of ε’’ at the UV ε’ = 0 wavelength λ1 [~250 nm for all compositions].

Figure 5: Optical properties of BST at telecoms wavelengths. Compositional dependence of (a, c) refractive index n and (b, d) extinction coefficient κ at (a, b) 1310 and (c, d) 1550 nm.

Figure 6: Performance of BST alloys as plasmonic and high-index dielectric media. Spectral dispersion of figures of merit [F1, F2, F3] relating to the ability of BST and a selection of other materials [as labelled] to support (a) propagating surface plasmon polaritons at a vacuum interface [F1]; (b) localized, spherical nanoparticle surface plasmons [F2]; (c) low-loss propagating light waves [F3]. Blue areas encompass all ternary and binary BST compositions analysed within the present study [see Figure 2b]. Dashed blue lines correspond to the particular compositions achieving maximum values of the figures of merit within the UV-NIR spectral range under consideration. Data for other materials is taken from literature as follows: Ag and Au from Ref. [50]; Al from Ref. [51]); TiN from Ref. [52]; TCOs - AZO, GZO and ITO from Ref. [53]; Si from Ref. [54]; Ge optical constants were measured by variable-angle spectroscopic ellipsometry for a Ge film with a thickness of 160 nm deposited by resistive evaporation.



Geographic location of data collection: University of Southampton, U.K.

Related projects:
The Physics & Technology of Photonic Metadevices & Metasystems
Hayden, B., Richardson, D., Zheludev, N., Plum, E. & Muskens, O.
EPSRC
EP/M009122/1

National Hub in High Value Photonic Manufacturing
charlton, M.D.B., Sahu, J., Zervas, M., Reed, G.T., Mashanovich, G., Heffernan, J., Poletti, F., Richardson, D.J., Hewak, D., Brambilla, G., Zheludev, N.
EPSRC
EP/N00762X/1


Dataset available under a CC BY 4.0 licence


Publisher: University of Southampton, U.K.


Date: February 2019