First-principles study on electronic and optical properties of Cu2ZnSiV I4 (VI=S, Se, and Te) quaternary semiconductors

Zhang, Xuebiao; Rao, Dewei; Lu, Ruifeng; Deng, Kuan; Chen, Dongguo

doi:10.1063/1.4920936

Cited by 14 publications

(12 citation statements)

References 25 publications

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“…On the other hand, it can be noted from Table that the tetragonal distortion parameter η = c /2 a is smaller than unity ( η = 0.995) for the present α‐Cu 2 ZnGeTe 4 with KS structure. This is consistent with first principles electronic structure calculations for

C u_{2} B^{I I} C^{I V} X_{4}^{V I}

quaternaries indicating that in general η < 1 for the KS but η > 1 for the ST structure. For example, for Cu 2 ZnGeTe 4 the calculated value of η is 0.994 for KS and 1.003 for ST structures .…”

Section: Resultssupporting

confidence: 89%

“…These compounds are known to crystallize either in tetragonal structures (space groups I

\overset{4}{true}

2 m , P

\overset{4}{true}

, or I

\overset{4}{true}

) or in the orthorhombic wurtz–stannite superstructure (space group Pmn 2 1 ) which are derived from the sphalerite or wurtzite cells, respectively, by ordering of the metals on the cation sites. Minor attention has been devoted to the Cu 2 B II C IV Te 4 members of this family and their physical and chemical properties were only scarcely discussed in the literature . However, the phase relations and crystal structure of the compound Cu 2 ZnGeTe 4 have been studied in some detail by Parasyuk et al by using differential thermal analysis (DTA) and X‐ray powder diffraction (XRD) techniques.…”

Section: Introductionmentioning

confidence: 99%

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Structural characterization of the high‐temperature modification of the Cu₂ZnGeTe₄ quaternary semiconductor compound

Nieves

Delgado

Marcano

et al. 2016

Physica Status Solidi (b)

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A combined study of the X-ray powder diffraction, differential thermal analysis, optical absorption, and Raman spectroscopy of the high-temperature modification of Cu 2 ZnGeTe 4 quaternary semiconductor, obtained by fast quenching from 820 K to ice water temperature, has been done. It has been found that this phase crystallizes in a tetragonal kesterite-type structure. From the analysis of the absorption coefficient spectra, the band gap energy of this material at room temperature has been found to be 1.49 eV. An optical transition from defect acceptor states to the conduction band is also observed below the fundamental absorption edge. Three strongest Raman lines observed at 116, 119, and 139 cm À1 have been assigned to the A-symmetry modes. Also, lines at 81, 89, 97, and 263 cm À1 tentatively ascribed as B or E-symmetry modes have been detected from the spectrum. The presence in this hightemperature modification of ZnTe and Cu 2 GeTe 3 secondary phases has been detected by both XRD and Raman spectroscopy.

show abstract

C u_{2} B^{I I} C^{I V} X_{4}^{V I}

Section: Resultssupporting

confidence: 89%

“…These compounds are known to crystallize either in tetragonal structures (space groups I

\overset{4}{true}

2 m , P

\overset{4}{true}

, or I

\overset{4}{true}

Section: Introductionmentioning

confidence: 99%

Structural characterization of the high‐temperature modification of the Cu₂ZnGeTe₄ quaternary semiconductor compound

Nieves

Delgado

Marcano

et al. 2016

Physica Status Solidi (b)

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“…1 [6] and theoretical studies [7]. As expected, the lattice constants decrease monotonically and almost linearly for increasing Ge and Si-content because of the larger atomic covalent radius of Sn (1.45 Å) compared to those of Ge (1.25 Å) and Si (1.10 Å).…”

Section: Computational Detailsmentioning

confidence: 62%

“…Incorporation of Ge or Si in CZTSSe has been suggested as one way to increase the PCE as well as the crystalline stability of high‐quality CZTSSe . For instance, by alloying Sn with Ge atoms in CZTSe, the band‐gap energy of Cu 2 ZnSn 1− x Ge x Se 4 can be varied from 1.1 to 1.45 eV when increasing x from 0 to 1 .…”

Section: Introductionmentioning

confidence: 99%

Investigation of the structural, optical and electronic properties of Cu₂Zn(Sn,Si/Ge)(S/Se)₄alloys for solar cell applications

Zamulko

Chen

Persson

2017

Physica Status Solidi (b)

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The crystalline structural, electronic and optical properties of the alloys Cu2ZnSn1−xGexS4, Cu2ZnSn1−xSixS4, Cu2ZnSn1−xGexSe4 and Cu2ZnSn1−xSixSe4 are calculated by first‐principles using both the generalized gradient approximation and a hybrid functional approach. We find that the electronic band structures are qualitatively very similar for these alloys. The band‐gap energy Eg(x) (for x = 0, 0.125, 0.25, 0.5, 0.75, 0.875 and 1) increases almost linearly with Ge and Si substitution. However, for very Si rich Cu2ZnSn1−xSixS4 alloys (but not for Cu2ZnSn1−xSixSe4) there is an abrupt increase of Eg(x) for x > 0.96. We therefore analyse this effect by calculating the electronic structures for x = 0.93, 0.96 and 1. We find that the Sn‐like states form localised density‐of‐states below the conduction band edge in Cu2ZnSn1−xSixS4, while corresponding states resonate more with the conduction bands in Cu2ZnSn1−xSixSe4. The effect in S‐based alloys is a direct consequence of the energetically high conduction band edge for Cu2ZnSiS4 in combination with energetically low Sn‐like states. Furthermore, the calculated dielectric constants are relatively similar for all alloy configurations. Overall however, our results suggest that it is possible to use Si and Ge as alloying element in quaternary Cu2ZnSnS4 to improve the photovoltaic properties.

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“…alloys. Incorporation of Ge or Si in CZTSSe has been suggested as one way to increase the solar cell efficiency as well as the crystalline stability of high-quality CZTSSe [14][15][16][17][18][19][20]. It has been shown that the presence of Ge in CZTSe (i.e., Se as anions) can tune the gap energy to be close to the optimal value of ~1.3 eV [15,17,19] with an improved stability of the absorber layer in solar cells [16].…”

Section: Czts Cation Alloysmentioning

confidence: 99%

Solar Energy Capture Materials

2019

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Herein we investigate the structural, electronic, and optical properties of emerging copper-based chalcogenides, employing atomistic first-principles computational method within the density functional theory. The fundamental material characteristics of the compounds are analysed, and the optoelectronic performances are improved by alloying with isovalent elements. In order to develop inorganic photovoltaics based on ultrathin photon-absorbing film (i. e., with thicknesses d < 100 nm), the material shall exhibit optimized band-gap energy Eg as well as having a very high absorption coefficient α(ω), especially for photons energies in the lower spectrum: Eg ≤ E < (Eg + 2 eV). To develop high-efficient solar cells we therefore suggest to tailor-make the materials to form direct gap multi-valley band edges, and energy bands with rather flat dispersions. That can typically be achieved by considering alloys with heavy elements that have relatively localized sp-like orbitals. With such tailored materials, we demonstrate that it is possible to reach a theoretical maximum efficiency as high as ηmax ≈ 30% for film thicknesses of d ≈ 50-100 nm. 4.1 Introduction In this work, we theoretically investigate inorganic solar cell materials by means of first-principles atomistic methods within the framework of the density functional theory (DFT). The aim is to further accelerate the progress of developing environmentally friendly p-n junction photovoltaics (PV), especially towards technologies with high-efficient and inexpensive ultrathin films. Crystalline silicon (c-Si) is today by far the most commercialized materials in PV modules with above 90% of the market [1], despite having indirect gap with band-gap energy Eg ≈ 1.2 eV. For laboratory solar cell, the energy conversion efficiency for single crystal c-Si without concentrator is ηmax = 25.8% (Rev. 10-30-2017 [2]), but the active absorber material is rather thick, often 100-200 μm due to insufficient absorption. Thin-film PV technologies rely on 100 times thinner layer (typically around 1 μm), and the absorbers must therefore have higher capacity to absorb the sunlight in the energy region from ~1 to ~3 eV. The most traditional inorganic solar cells [2] are based on either amorphous silicon (a-Si or its hydrogenated compound a-Si:H with Eg = 1.7 eV and ηmax = 14.0%), cadmium telluride (CdTe; Eg = 1.5 eV and ηmax = 22.1%), thin-film gallium arsenide (GaAs; Eg = 1.5 eV and ηmax = 28.8%), or copper indium gallium selenide (CuIn1-xGaxSe2; Eg ≈ 1.2 eV for x = 0.3 and ηmax = 22.6%), and these materials have their "pros and cons" in terms of prospective large-scale production. Developments of even thinner absorber materials, i.e., for ultrathin inorganic solar cells, is an emerging concept to produce competitive PV cells or to complement the c-Si technologies with a proper top-cell in tandem structures. Here, ultrathin implies absorber layers with thicknesses less than 100 nm (perhaps as thin as 10-30 nm), which is then at least more than 10 times thinner than in the traditional thin...

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First-principles study on electronic and optical properties of Cu2ZnSiV I4 (VI=S, Se, and Te) quaternary semiconductors

Cited by 14 publications

References 25 publications

Structural characterization of the high‐temperature modification of the Cu₂ZnGeTe₄ quaternary semiconductor compound

Structural characterization of the high‐temperature modification of the Cu₂ZnGeTe₄ quaternary semiconductor compound

Investigation of the structural, optical and electronic properties of Cu₂Zn(Sn,Si/Ge)(S/Se)₄alloys for solar cell applications

Solar Energy Capture Materials

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First-principles study on electronic and optical properties of Cu2ZnSiV I4 (VI=S, Se, and Te) quaternary semiconductors

Cited by 14 publications

References 25 publications

Structural characterization of the high‐temperature modification of the Cu2ZnGeTe4 quaternary semiconductor compound

Structural characterization of the high‐temperature modification of the Cu2ZnGeTe4 quaternary semiconductor compound

Investigation of the structural, optical and electronic properties of Cu2Zn(Sn,Si/Ge)(S/Se)4alloys for solar cell applications

Solar Energy Capture Materials

Contact Info

Product

Resources

About

Structural characterization of the high‐temperature modification of the Cu₂ZnGeTe₄ quaternary semiconductor compound

Structural characterization of the high‐temperature modification of the Cu₂ZnGeTe₄ quaternary semiconductor compound

Investigation of the structural, optical and electronic properties of Cu₂Zn(Sn,Si/Ge)(S/Se)₄alloys for solar cell applications