Phase correlations in the CuAlSe₂–CuAlTe₂ system

Abstract

Alloys in the CuAlSe 2 -CuAlTe 2 system were synthesized in BN-crucibles in silica tubes under vacuum to obtain the corresponding phase equilibria. X-ray powder diffraction and thermal analytic data of the T -x phase diagram revealed a complete solid solutions series in the subsolidus region. Within the CuAlSe 2x Te 2(1-x) system the refined lattice parameters a and c approximately obey the Vegard rule and also the cell volume and the heat of fusion confirm linear correlations with the composition of the mixed crystals. The anion position parameter calculated after S. C. Abrahams & J. L. Bernstein (u AB ) and J. E Jaffe & A. Zunger (u JZ ) is greater than 0.25 and reveals a linear dependence on composition. The liquidus part of the CuAlSe 2x Te 2(1-x) system with x < 0.35 exhibits vertical section behaviour with a ternary peritectic followed up by a ternary monotectic whereas the region with x > 0.35 shows quasibinary equilibria.

Wide Band Gap Chalcogenide Semiconductors

“…Plotted alongside are the II-Ch zincblende compounds discussed in section , and binary zincblende III–V semiconductors GaP, GaAs, and InP for reference. Note that the effects of band gap bowing in chalcopyrites are not plotted, but many of these band gap dependencies have been shown computationally and experimentally to be close to linear with bowing parameters usually less than 0.5 eV (see below). ,, Also, alloy band gaps are only drawn here between isostructural systems with one substitution, though nonisostructural and multicomponent alloying are regularly utilized across this space, for example, zincblende (Be,Mg,Zn)Se used for UV lasers and quinternary alloys CuAl x Ga 1– x (S 1– y Se y ) 2 . We briefly discuss three strategiesalloying I, III, or Ch ionsand mention representative chalcopyrite alloys.…”

“…Note that the effects of band gap bowing in chalcopyrites are not plotted, but many of these band gap dependencies have been shown computationally and experimentally to be close to linear with bowing parameters usually less than 0.5 eV (see below). 238,284,285 Also, alloy band gaps are only drawn here between isostructural systems with one substitution, though nonisostructural and multicomponent alloying are regularly utilized across this space, for example, zincblende (Be,Mg,Zn)Se used for UV lasers 286 and quinternary alloys CuAl x Ga 1−x (S 1−y Se y ) 2 . 287 We briefly discuss three strategiesalloying I, III, or Ch ionsand mention representative chalcopyrite alloys.…”

Optical absorption and photoluminescence of CuAlTe 2

“…1) with the lattice constants a and c at room temperature equal 6.023(5) and 11.91(1) Å, respectively. This is in accordance with the results of paper [15]. The upper line of Bragg positions refers to reflexes of the chalcopyrite type structure, and the lower line refers to the reflexes of Si, which was used as an internal standard.…”

Growth and optical properties of CuAlTe2

“…There are two serious problems for growing good quality CuAlTe 2 crystals. The first is that in peritectic reaction at 1183 K, CuAlTe 2 decomposes to the 0.97 Cu 2 Te 0.03 Al 2 Te 3 alloy with the structure of Cu 2 Te and to an Al 2 Te 3 ‐enriched alloy with the composition close to 0.40 Cu 2 Te 0.60 Al 2 Te 3 12. The second reason is that the reaction of CuAlTe 2 ternary‐compound formation from the elements goes through the initial formation of binary compounds, including the formation of a phase with variable composition Cu 2– x Te.…”