Ternary Diamond-Like Semiconductors / Troinye Almazopodobnye Poluprovodniki / Тройные Алмазоподобные Полупроволники

Berger, Lev I.; Prochukhan, V. D.

doi:10.1007/978-1-4757-0040-4

Cited by 22 publications

(29 citation statements)

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“…Previously, a similar band gap was reported by Berger et al using the optical method. 31 We have also noticed that a much smaller gap of 0.13 eV was suggested by Nakanishi et al by analyzing the temperature dependence of electrical resistivity and Hall coefcient, and 0.11 eV via the infrared transmission spectra. 32 A similar value was also obtained by Li et al by tting the electrical resistivity against temperature.…”

Section: Resultsmentioning

confidence: 58%

Thermoelectric properties of Sn-doped p-type Cu₃SbSe₄: a compound with large effective mass and small band gap

et al. 2014

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Cu 3 SbSe 4 -based compounds composed of earth-abundant elements have been found to exhibit good thermoelectric performance at medium temperatures. High zT values were achieved in previous studies, but further insight into the transport mechanism as well as some key material parameters is still needed. In this work, we studied the electrical and thermal transport properties of Sn-doped Cu 3 SbSe 4 between 300 K and 673 K. It was found that the single parabolic band model explains the electrical transport very well.Experimentally, we determined the band gap to be around 0.29 eV. The density-of-state effective mass was found to be about 1.5 m e for the doped samples. The transport properties suggested degeneracy splitting near the valence band maximum that was not captured by previous band structure calculations.The maximum zT $ 0.70 was obtained at 673 K, and the optimized carrier density was $1.8 Â 10 20 cm À3, and the potential for further improvement of zT via material engineering is briefly discussed.

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Section: Resultsmentioning

confidence: 58%

Thermoelectric properties of Sn-doped p-type Cu₃SbSe₄: a compound with large effective mass and small band gap

et al. 2014

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“…18 The high temperature phase is a disordered face centered cubic (fcc) structure (space group F-43m) and low temperature structure is the ordered orthorhombic Imm2 phase. In addition, as the Ge content is increased in Cu 2 Ge 1+x Se 3 , a structural phase transition takes place resulting in conversion of the orthorhombic cell to the fcc structure with a unit cell parameter of ~ 5.55 Å.…”

Section: Resultsmentioning

confidence: 99%

Thermoelectric properties and investigations of low thermal conductivity in Ga-doped Cu2GeSe3

et al. 2011

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In this study, we have synthesized a series of low thermal conductivity diamond-like materials with the general formula Cu 2 Ga x Ge 1-x Se 3 for 0 ≤ x ≤ 0.1, and their transport properties were evaluated to establish their suitability for TE based waste heat recovery applications. We report results for the Seebeck coefficient (S), electrical resistivity (ρ), thermal conductivity (κ), Hall coefficient (R H ), crystal structure, and elastic properties of Cu 2 Ga x Ge 1-x Se 3 for x = 0.01, 0.03, 0.05, 0.07 and 0.1. Powder x-ray diffraction revealed that a small amount of a related cubic polymorph appeared along with the orthorhombic parent phase at high Ga concentrations. This cubic phase is related to the parent phase in that both contain three-dimensional tetrahedral diamond-like substructures. All samples showed positive values of S and R H over the entire temperature range studied, indicative of p-type charge carriers. The largest value of S = 446 μVK -1 was observed at 745 K for undoped Cu 2 GeSe 3 . With increasing Ga content, both S and ρ decreased. Low values of κ were observed for all samples with the lowest value of κ = 0.67 W m -1 K -1 at 745 K for undoped Cu 2 GeSe 3 . This value approaches the theoretical minimum thermal conductivity for these materials at high temperatures. Although this diamondlike material has highly symmetric, lower coordination number tetrahedral bonding, an unusually large Grüneisen parameter (γ), a measure of bonding anharmonicity, was observed for Cu 2 Ga 0.1 Ge 0.9 Se 3 . A value of γ = 1.7 was calculated from the measured values of the elastic properties, heat capacity, and volume thermal expansion. Given the fact that all materials investigated have similar elastic property values and likely comparable coefficients of thermal expansion we surmise that this large Grüneisen parameter is a general feature for this material system. We conclude that this high level of anharmonicity gives rise to enhanced phononphonon scattering that is, in addition to the scattering brought about by the disordered structure, resulting in very low values of thermal conductivity.

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“…The II-IV-V 2 and I-III-VI 2 compounds based on the zincblende lattice are well known to order in the chalcopyrite structure 1,2 and have received significant attention for their nonlinear optical properties and photovoltaic applications. For example, Cu(In,Ga)(S,Se) 2 thin films are widely used in photovoltaics [3][4][5] and ZnGeP 2 , CdGeAs 2 and AgGa(Se,Te) 2 single crystals are used as frequency doublers and parametric oscillators in nonlinear optical applications.…”

Section: Introductionmentioning

confidence: 99%

“…[6][7][8] Order-disorder transitions of these chalcopyrite materials have been reported, with the disordered state apparently exhibiting the binary, parent zincblende structure in x-ray diffraction spectra. 1,2 The accepted model, first proposed by Buerger in 1934, is that the cations undergo entropy-driven randomization of their positions in the two cation sublattices. 9 This randomization is necessarily accompanied by many local violations of the octet rule, although the rule is observed on average, for stoichiometric material.…”

Section: Introductionmentioning

confidence: 99%

Charge-neutral disorder and polytypes in heterovalent wurtzite-based ternary semiconductors: The importance of the octet rule

et al. 2015

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We investigate lattice ordering phenomena for the heterovalent ternaries that are based on the wurtzite lattice, under the constraint that the octet rule be preserved. We show that, with the single exception of a highly symmetric twinned structure, all allowed lattice orderings can be described by a pseudospin model corresponding to the two different stackings of ABAB rows of atoms in the basal plane that occur in the P na21 and P mc21 crystal structures. First-principles calculations show that the difference in the energies of formation between these two structures is 13±3 meV/fu (formula unit) for ZnSnN2 and is an order of magnitude larger for ZnGeN2, and that for both materials the P m31 structure, which contains only octet-rule-violating tetrahedra, has a significantly higher energy of formation and a signficantly lower band gap. We predict almost random stacking and wurtzite-like x-ray diffraction spectra in the case of ZnSnN2, consistent with reported measurements. The octet-rule-preserving model of disorder proposed here predicts a band gap that for ZnSnN2 is relatively insensitive to ordering, in contrast to the prevailing model, which invokes the random placement of atoms on the cation sublattice. The violations of the octet rule in the latter model lead to significant narrowing of the band gap. The Raman and photoluminescence spectra of ZnSnN2 are interpreted in light of the ordering model developed here. The observation that ZnGeN2 orders in the P na21 structure under appropriate growth conditions is consistent with the larger difference in the energies of formation of the P na21 and P mc21 structures for this material. The ordering model presented here has important implications for the optical, electronic and lattice properties of all wurtzite-based heterovalent ternaries.

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Ternary Diamond-Like Semiconductors / Troinye Almazopodobnye Poluprovodniki / Тройные Алмазоподобные Полупроволники

Cited by 22 publications

References 0 publications

Thermoelectric properties of Sn-doped p-type Cu₃SbSe₄: a compound with large effective mass and small band gap

Thermoelectric properties of Sn-doped p-type Cu₃SbSe₄: a compound with large effective mass and small band gap

Thermoelectric properties and investigations of low thermal conductivity in Ga-doped Cu2GeSe3

Charge-neutral disorder and polytypes in heterovalent wurtzite-based ternary semiconductors: The importance of the octet rule

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Ternary Diamond-Like Semiconductors / Troinye Almazopodobnye Poluprovodniki / Тройные Алмазоподобные Полупроволники

Cited by 22 publications

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Thermoelectric properties of Sn-doped p-type Cu3SbSe4: a compound with large effective mass and small band gap

Thermoelectric properties of Sn-doped p-type Cu3SbSe4: a compound with large effective mass and small band gap

Thermoelectric properties and investigations of low thermal conductivity in Ga-doped Cu2GeSe3

Charge-neutral disorder and polytypes in heterovalent wurtzite-based ternary semiconductors: The importance of the octet rule

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Thermoelectric properties of Sn-doped p-type Cu₃SbSe₄: a compound with large effective mass and small band gap

Thermoelectric properties of Sn-doped p-type Cu₃SbSe₄: a compound with large effective mass and small band gap