Band gap of sphalerite and chalcopyrite phases of epitaxial ZnSnP2

St-Jean, P.; Seryogin, G. A.; Francoeur, S.

doi:10.1063/1.3442917

Cited by 34 publications

(31 citation statements)

References 12 publications

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“…The pattern at the bottom is the simulated orthorhombic pattern for the space group P na2 1 using the lattice parameters found for growth experiment 4 in Table 2 peaks, and the wurtzite phase was constrained to have the same lattice parameter and peak width as the disordered material of growth experiment 1. Researchers studying ZnSnP 2 also found evidence of phase separation of the ordered chalcopyrite and disordered sphalerite structures [3]. Growth experiments 3 and 4 were each fit well by the single orthorhombic P na2 1 phase.…”

Section: Characterization Methodsmentioning

confidence: 78%

Characterization and control of ZnGeN2 cation lattice ordering

Blanton

Shan

et al. 2017

Journal of Crystal Growth

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ZnGeN2 and other heterovalent ternary semiconductors have important potential applications in optoelectronics, but ordering of the cation sublattice, which can affect the band gap, lattice parameters, and phonons, is not yet well understood. Here the effects of growth and processing conditions on the ordering of the ZnGeN2 cation sublattice were investigated using x-ray diffraction and Raman spectroscopy. Polycrystalline ZnGeN2 was grown by exposing solid Ge to Zn and NH3 vapors at temperatures between 758 degree C and 914 degree C. Crystallites tended to be rod-shaped, with growth rates higher along the c-axis. The degree of ordering, from disordered, wurtzite-like x-ray diffraction spectra to orthorhombic, with space group Pna21, increased with increasing growth temperature, as evidenced by the appearance of superstructure peaks and peak splittings in the diffraction patterns. Annealing disordered, low-temperature-grown ZnGeN2 at 850 degree C resulted in increased cation ordering. Growth of ZnGeN2 on a liquid Sn-Ge-Zn alloy at 758 degree C showed an increase in the tendency for cation ordering at a lower growth temperature, and resulted in hexagonal platelet-shaped crystals. The trends shown here may help to guide understanding of the synthesis and characterization of other heterovalent ternary nitride semiconductors as well as ZnGeN2.Comment: 13 pages, 7 figure

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Section: Characterization Methodsmentioning

confidence: 78%

Characterization and control of ZnGeN2 cation lattice ordering

Blanton

Shan

et al. 2017

Journal of Crystal Growth

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“…4 How ever, comparatively little attention has been focused on the II-IV-V 2 (II ¼ Zn, Cd; IV ¼ Si, Ge, Sn, and V ¼ N, P, As, or Sb) chalcopyrite structured materials, which offer additional chemical flexibility. ZnSnP 2 , which crystallizes in the chal copyrite structure, has been reported to possess a bandgap of 1.68 eV, 5 which is close to the optimum bandgap of 1.5 eV for a single-junction solar cell.…”

mentioning

confidence: 90%

“…6 In SP-ZSP, the Sn and Zn atoms are randomly dis tributed over the cation sub-lattice, and the disordered phase has been reported to exhibit a bandgap ranging from 1.22 eV to 1.38 eV. 5,7 The phenomenon of tunable disorder is well known for semiconductor alloys. 8 Unusually for a chalcopyrite structured material, ZnSnP 2 does not display any tetragonal distortion (i.e., c ¼ 2a), and so the lattice constant for both the chaclopyr ite and cubic sphalerite systems is nearly perfectly matched.…”

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confidence: 99%

Bandgap engineering of ZnSnP2 for high-efficiency solar cells

Scanlon¹,

Walsh²

2012

Applied Physics Letters

120

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ZnSnP2, an absorber material for solar cells, transitions from an ordered chalcopyrite to a disordered sphalerite structure at high temperatures. We investigate the electronic structure of both phases, combining a screened hybrid density functional with the special quasi-random structure method. We predict a bandgap reduction of 0.95 eV between the ordered and fully disordered materials. Experimental reports are consistent with partial disorder. Tuning of the order parameter would lead to a family of ZnSnP2 phases with bandgaps ranging from 0.75 eV to 1.70 eV, thus providing graded solar cell absorbers from a single material system.

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“…Studies using other methods yield data that conflict with the random disorder model. For example, band-gap measurements of ZnSnP 2 show decreases of 18% and 22% when comparing ordered samples with disordered (Ryan et al, 1987;St-Jean et al, 2010). DFT calculations based on the random model predict much larger decreases in band gap for the two cases of 56% and 76% (Scanlon & Walsh, 2012;Ma et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Domain formation and phase transitions in the wurtzite-based heterovalent ternaries: a Landau theory analysis

Quayle

2020

Acta Cryst Sect A

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Characterizing the crystalline disorder properties of heterovalent ternary semiconductors continues to challenge solid-state theory. Here, a Landau theory is developed for the wurtzite-based ternary semiconductor ZnSnN 2 . It is shown that the symmetry properties of two nearly co-stable phases, with space groups Pmc2 1 and Pbn2 1 , imply that a reconstructive phase transition is the source of crystal structure disorder via a mixture of phase domains. The site exchange defect, which consists of two adjacent antisite defects, is identified as the nucleation mechanism of the transition. A Landau potential based on the spacegroup symmetries of the Pmc2 1 and Pbn2 1 phases is constructed from the online databases in the ISOTROPY software suite and this potential is consistent with a system that undergoes a paraelectric to antiferroelectric phase transition. It is hypothesized that the low-temperature Pbn2 1 phase is antiferroelectric within the c-axis basal plane. The dipole arrangements within the Pbn2 1 basal plane yield a nonpolar spontaneous polarization and the electrical susceptibility derived from the Landau potential exhibits a singularity at the Né el temperature characteristic of antiferroelectric behavior. These results inform the study of disorder in the broad class of heterovalent ternary semiconductors, including those based on the zincblende structure, and open the door to the application of the ternaries in new technology spaces.

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Band gap of sphalerite and chalcopyrite phases of epitaxial ZnSnP2

Cited by 34 publications

References 12 publications

Characterization and control of ZnGeN2 cation lattice ordering

Characterization and control of ZnGeN2 cation lattice ordering

Bandgap engineering of ZnSnP2 for high-efficiency solar cells

Domain formation and phase transitions in the wurtzite-based heterovalent ternaries: a Landau theory analysis

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