An electron microscope examination of scandium sesquisulphide, Sc₂S₃, and its mode of disordering in the electron beam

Abstract

110] zone-axis structure images of the semiconductor compound Sc2S3 show the ordered arrangement of the unoccupied cation positions, which gives rise to a superlattice of the NaCl (B1, ScS) structure in three dimensions. The experimental images are adequately simulated by multislice computations. Electron-beam irradiation damages the crystal and the image changes in a complex way. Significant structural changes were directly observed in lattice images and diffraction patterns. Some of this resembles the disorder, believed to be grown in, which consists of antiphase boundaries resulting from the systematic displacement of slabs of structure. [For single crystal: a = 10.376 (2), b = 7.3775 (9), c = 22.033 (6) A.]

Evolution of Structural, Thermal, Optical, and Vibrational Properties of Sc2S3, ScCuS2, and BaScCuS3 Semiconductors

“…Two bandgaps were previously determined in single crystal of ScCuS 2 , namely, 2.3 eV direct bandgap and 1.8 eV indirect bandgap. [18] Our measurement on powder sample indicates the bandgap of 2.05 eV (Figure 8). Ab initio calculations using HSE06, however, indicate larger direct bandgap; earlier calculations by Scanlon predicted direct bandgap as wide as 2.78 eV, and our calculations predict value slightly closer to the experiment, namely, 2.35 eV.…”

“…[10][11][12] Scandium has a wide range of inorganic solids with other chemical elements. [13][14][15][16][17][18] The Sc 2 S 3 sulfide with the NaCl superstructure has orthorhombic crystal system, space group Fddd (70); a = 7.378 Å, b = 10.376 Å, c = 22.053 Å. [19] The CuScS 2 compound crystallizes in the P3m1 hexagonal space group with a = 3.734 Å, c = 6.102 Å.…”

Single Crystals of EuScCuSe3: Synthesis, Experimental and DFT Investigations

“…Trivalent scandium differs from other trivalent cations of the first transition series due to the presence of a closed outer electron shell with an argon configuration. Scandium chalcogenides are p -type [ 2 , 4 , 9 , 10 , 11 ] and n -type [ 8 ] semiconductors. Doping with heavy metals results in n -type conduction with low resistivity [ 9 ] in compounds that exhibit metallic properties [ 12 ].…”

“…The structure is represented by layers 2D-[CuTiS 3 ] – consisting of alternating pairs of distorted tetrahedra [CuS 4 ] 7– and octahedra [TiS 6 ] 8– in the direction [001], which are separated by single-capped trigonal prisms [NaS 7 ] 13– [ 21 ]. However, previously synthesized quaternary scandium chalcogenides EuScCuS 3 [ 11 ], SrScCuS 3 [ 11 , 22 ], SrScCuSe 3 [ 1 , 23 ], BaScCuS 3 [ 24 ] crystallize in the space group Cmcm with structure type of KZrCuS 3 . Since the ionic radius of Eu 2+ ( r i (Eu 2+ ) = 1.17 Å, C.N.…”