Electronic structure of binary and ternary components of CdTe:O thin films

Menéndez-Proupín, E.; Gutiérrez, Gonzalo; Palmero, Ester M.; Peña, J. L.

doi:10.1002/pssc.200304873

Cited by 7 publications

(3 citation statements)

References 17 publications

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“…CdTe is an “archetypical II–VI” material with a VBM mostly comprising bonding cation-p/anion-p states and a CBM mostly comprising antibonding cation-s/anion-p states, with the corresponding antibonding (bonding) states occurring higher (lower) in the CB (VB) with respect to the band edge. , The cation-d orbitals of CdTe are bound too strongly to significantly interact with valence states and therefore do not influence the VBM. However, in the copper-containing compounds (CIGS, CZTS, CAS, and CBS), the full Cu d states are close in energy to the full anion-p orbitals.…”

Section: Results and Discussionmentioning

confidence: 99%

Band Alignments, Band Gap, Core Levels, and Valence Band States in Cu₃BiS₃ for Photovoltaics

Whittles

Veal

Savory

et al. 2019

ACS Appl. Mater. Interfaces

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The earth-abundant semiconductor Cu3BiS3 (CBS) exhibits promising photovoltaic properties and is often considered analogous to the solar absorbers copper indium gallium diselenide (CIGS) and copper zinc tin sulfide (CZTS) despite few device reports. The extent to which this is justifiable is explored via a thorough X-ray photoemission spectroscopy (XPS) analysis: spanning core levels, ionization potential, work function, surface contamination, cleaning, band alignment, and valence-band density of states. The XPS analysis overcomes and addresses the shortcomings of prior XPS studies of this material. Temperature-dependent absorption spectra determine a 1.2 eV direct band gap at room temperature; the widely reported 1.4–1.5 eV band gap is attributed to weak transitions from the low density of states of the topmost valence band previously being undetected. Density functional theory HSE06 + SOC calculations determine the band structure, optical transitions, and well-fitted absorption and Raman spectra. Valence band XPS spectra and model calculations find the CBS bonding to be superficially similar to CIGS and CZTS, but the Bi3+ cations (and formally occupied Bi 6s orbital) have fundamental impacts: giving a low ionization potential (4.98 eV), suggesting that the CdS window layer favored for CIGS and CZTS gives detrimental band alignment and should be rejected in favor of a better aligned material in order for CBS devices to progress.

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Section: Results and Discussionmentioning

confidence: 99%

Band Alignments, Band Gap, Core Levels, and Valence Band States in Cu₃BiS₃ for Photovoltaics

Whittles

Veal

Savory

et al. 2019

ACS Appl. Mater. Interfaces

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“…Figure 6 shows that TeO 2 is bonded to four oxygen atoms, while TeO 4 and TeO 3 have six bonds each, with the difference that TeO 4 has one non-bridging oxygen, that is, it is bonded to only one oxygen atom. The ternary crystals of CdTeO 3 and CdTe 3 O 8 have only Cd-O and Te-O bonds, but no Cd-Te bonds [72]. On this basis, it can be assumed that the oxides CdO and TeO 4 initially form on the surface and later evolve into TeO 2 and TeO 3 when saturated with oxygen.…”

Section: Discussionmentioning

confidence: 99%

Characterization of CdxTeyOz/CdS/ZnO Heterostructures Synthesized by the SILAR Method

et al. 2023

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CdxTeyOz/CdS/ZnO heterostructures were obtained by the SILAR method using ionic electrolytes. A CdS film was formed as a buffer layer for better adhesion of the cadmium-tellurium oxides to the substrate surface. In turn, the ZnO substrate was previously prepared by electrochemical etching to form a rough textured surface. In addition, an annealing mode was used in an oxygen stream to complete the oxidation process of the heterostructure surface. The resulting nanocomposite was investigated using RAMAN, XRD, SEM, and EDX methods. We assume that the oxides CdO and TeO4 initially form on the surface and later evolve into TeO2 and TeO3 when saturated with oxygen. These oxides, in turn, are the components of the ternary oxides CdTeO3 and CdTe3O8. It should be noted that this mechanism has not been fully studied and requires further research. However, the results presented in this article make it possible to systematize the data and experimental observations regarding the formation of cadmium-tellurium films.

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“…It is evident that the charge distribution around Te shows symmetry related to the tetrahedral bonds. The Cd electron density includes a full semi-core 4d level and a depopulated 5s level, which produces an overall spherical symmetry around Cd [37]. CdTe has an iono-covalent chemical bond with ionicity coefficient 0.55 [38,39].…”

Section: About Cadmium Telluridementioning

confidence: 99%

Simulation for deposition of cadmium telluride thin films in hot wall epitaxial system using Monte Carlo technique

Venkatachalam¹,

Ganesan²,

Sakthivel³

2006

J. Phys. D: Appl. Phys.

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The molecular flow in the hot wall epitaxial system has been studied by computer simulation using the Monte Carlo technique for the deposition of CdTe thin films. The number of wall collisions, intermolecular collisions, direct transmissions, number of molecules and flux density distributions along each volume of the tube, with different source temperatures and wall temperatures for various lengths and radii of the hot wall setup, have been simulated, then the optimal deposition conditions for the thermodynamic equilibrium of vapour transport are determined and experimentally validated.

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Electronic structure of binary and ternary components of CdTe:O thin films

Cited by 7 publications

References 17 publications

Band Alignments, Band Gap, Core Levels, and Valence Band States in Cu₃BiS₃ for Photovoltaics

Band Alignments, Band Gap, Core Levels, and Valence Band States in Cu₃BiS₃ for Photovoltaics

Characterization of CdxTeyOz/CdS/ZnO Heterostructures Synthesized by the SILAR Method

Simulation for deposition of cadmium telluride thin films in hot wall epitaxial system using Monte Carlo technique

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Electronic structure of binary and ternary components of CdTe:O thin films

Cited by 7 publications

References 17 publications

Band Alignments, Band Gap, Core Levels, and Valence Band States in Cu3BiS3 for Photovoltaics

Band Alignments, Band Gap, Core Levels, and Valence Band States in Cu3BiS3 for Photovoltaics

Characterization of CdxTeyOz/CdS/ZnO Heterostructures Synthesized by the SILAR Method

Simulation for deposition of cadmium telluride thin films in hot wall epitaxial system using Monte Carlo technique

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Band Alignments, Band Gap, Core Levels, and Valence Band States in Cu₃BiS₃ for Photovoltaics

Band Alignments, Band Gap, Core Levels, and Valence Band States in Cu₃BiS₃ for Photovoltaics