Wurtzite-derived polytypes of kesterite and stannite quaternary chalcogenide semiconductors

Abstract

The I 2-II-IV-VI 4 quaternary chalcogenide semiconductors ͑e.g., Cu 2 ZnGeS 4 , Cu 2 ZnSnS 4 , Cu 2 ZnGeSe 4 Cu 2 CdSnSe 4 , and Ag 2 CdGeSe 4 ͒ have been studied for more than 40 years but the nature of their crystal structures has proved contentious. Literature reports exist for the stannite and kesterite mineral structures, which are zinc-blende-derived structures, and wurtzite-stannite, which is a wurtzite-derived structure. In this paper, through a global search based on the valence octet rule ͑local charge neutrality͒, we report a wurtzitederived structure corresponding to the kesterite structure, namely, wurtzite-kesterite ͑space group Pc͒, which is the ground state for some I 2-II-IV-VI 4 compounds, but is easily confused with the wurtzite-stannite ͑spacegroup Pmn2 1 ͒ structure. We show that there is a clear relationship between the properties of the wurtzitekesterite and zinc-blende-derived kesterite structures, as well as between wurtzite-stannite and stannite. Contributions from the strain and Coulomb energies are found to play an important role in determining the structural stability. The underlying trends can be explained according to the size and ionicity of the group-I,-II,-IV, and-VI atoms. Electronic-structure calculations show that the wurtzite-derived structures have properties similar to the zinc-blende-derived structures, but their band gaps are relatively larger, which has also been observed for binary II-VI semiconductors.

Phase-transition-driven growth of compound semiconductor crystals from ordered metastable nanorods

“…1a for a larger angle range). In the literature nanocrystals with orthorhombic wurtz-stannite and pseudo-orthorhombic wurtz-kesterite structures are reported [27][28][29][30][31] which produce similar diffraction signals due to a similar hexagonal anion sublattice, but differ in the ordering of the cations [30]. In our measurements, additional reflexes that indicate presence of wurtz-stannite or wurtz-kesterite instead of hexagonal wurtzite structure are not observed.…”

Interlaced crystals having a perfect Bravais lattice and complex chemical order revealed by real-space crystallography

“…From theory, ordered cations are favoured over random distributions of cations according to the Grimm-Sommerfeld (GS) or valence-octet rule 6 , which has been confirmed by density functional theory (DFT) calculations for bulk cubic I-III-VI 2 7,8 and related quaternary materials 9 . In cubic CuInS 2 thin films, X-ray diffraction (XRD) and transmission electron microscopy (TEM) 10 have established the coexistence of two ordered phases: chalcopyrite, which is the ground state, and a CuAu-like phase, which, according to theory 8 , is only slightly higher in energy.…”

Wurtzite Cu2ZnSnSe4 nanocrystals for high-performance organic–inorganic hybrid photodetectors

“…It has been predicted that Sn-containing quaternary chalcogenide compounds crystallize preferably in a sphalerite superstructure (zincblende-derived structures). 32 Hexagonal wurtzite CZTSe is a thermodynamically metastable phase, which is usually stable at very high temperature, whereas tetragonal stannite CZTSe is a more thermodynamically stable phase, which is stable at low temperature. Oleylamine is a strong ligand for Cu, Zn, Sn and Cd.…”