Abstract
We present the synthesis, crystal structures, and physical properties of Tl2Hg3Q4 (Q = S, Se, and Te). The incongruently melting Tl2Hg3Q4 crystals were grown in a TlxQ flux. These compounds are isostructural and crystallize in a monoclinic cell with a layered structure, adopting the space group C2/c with a = 11.493(2) Å, b = 6.6953(13) Å, c = 12.937(3) Å, β = 114.98(3)° for Tl2Hg3S4, a = 11.977(2) Å, b = 6.9264(14) Å, c = 13.203(3) Å, β = 116.36(3)° for Tl2Hg3Se4 and a = 12.648(3) Å, b = 7.3574(15) Å, c = 13.701(3) Å, β = 117.48(3)° for Tl 2Hg3Te4. The structures feature infinite chains of [Hg3Q4]2-, which are linked into layers by charge balancing Tl atoms. The compounds have very high densities (>8.3 g/cm3) with experimentally determined band gaps of 2.05, 1.57, and 0.90 eV for Q = S, Se, and Te, respectively. Using the refined crystal structures, we performed detailed band structure calculations at the density functional theory (DFT) level, using the screened-exchange local density approximation (sx-LDA). The results indicate that the compounds are semiconductors with the sulfur analog, having an indirect band gap, and the selenium and tellurium analogs, having direct energy band gaps. There is strong Hg 6s and Tl 6p orbital character in the conduction band minimum, while the valence band maximum has predominantly chalcogen p state character mixed in with a Tl 6s contribution. The band structure calculations support the experimental observation of a narrowing of the band gap in the series Q = S, Se, and Te, which results from the increasing extension of the outermost chalcogen p orbitals.
| Original language | English |
|---|---|
| Pages (from-to) | 4375-4383 |
| Number of pages | 9 |
| Journal | Chemistry of Materials |
| Volume | 23 |
| Issue number | 19 |
| DOIs | |
| Publication status | Published - Oct 11 2011 |
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Keywords
- cadmium telluride
- chalcogenide
- crystal growth
- X-ray detector
ASJC Scopus subject areas
- Materials Chemistry
- Chemical Engineering(all)
- Chemistry(all)
Cite this
Tl2Hg3Q4 (Q = S, Se, and Te) : High-density, wide-band-gap semiconductors. / Johnsen, Simon; Peter, Sebastian C.; Nguyen, Sandy L.; Song, Jung Hwan; Jin, Hosub; Freeman, Arthur J; Kanatzidis, Mercouri G.
In: Chemistry of Materials, Vol. 23, No. 19, 11.10.2011, p. 4375-4383.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Tl2Hg3Q4 (Q = S, Se, and Te)
T2 - High-density, wide-band-gap semiconductors
AU - Johnsen, Simon
AU - Peter, Sebastian C.
AU - Nguyen, Sandy L.
AU - Song, Jung Hwan
AU - Jin, Hosub
AU - Freeman, Arthur J
AU - Kanatzidis, Mercouri G
PY - 2011/10/11
Y1 - 2011/10/11
N2 - We present the synthesis, crystal structures, and physical properties of Tl2Hg3Q4 (Q = S, Se, and Te). The incongruently melting Tl2Hg3Q4 crystals were grown in a TlxQ flux. These compounds are isostructural and crystallize in a monoclinic cell with a layered structure, adopting the space group C2/c with a = 11.493(2) Å, b = 6.6953(13) Å, c = 12.937(3) Å, β = 114.98(3)° for Tl2Hg3S4, a = 11.977(2) Å, b = 6.9264(14) Å, c = 13.203(3) Å, β = 116.36(3)° for Tl2Hg3Se4 and a = 12.648(3) Å, b = 7.3574(15) Å, c = 13.701(3) Å, β = 117.48(3)° for Tl 2Hg3Te4. The structures feature infinite chains of [Hg3Q4]2-, which are linked into layers by charge balancing Tl atoms. The compounds have very high densities (>8.3 g/cm3) with experimentally determined band gaps of 2.05, 1.57, and 0.90 eV for Q = S, Se, and Te, respectively. Using the refined crystal structures, we performed detailed band structure calculations at the density functional theory (DFT) level, using the screened-exchange local density approximation (sx-LDA). The results indicate that the compounds are semiconductors with the sulfur analog, having an indirect band gap, and the selenium and tellurium analogs, having direct energy band gaps. There is strong Hg 6s and Tl 6p orbital character in the conduction band minimum, while the valence band maximum has predominantly chalcogen p state character mixed in with a Tl 6s contribution. The band structure calculations support the experimental observation of a narrowing of the band gap in the series Q = S, Se, and Te, which results from the increasing extension of the outermost chalcogen p orbitals.
AB - We present the synthesis, crystal structures, and physical properties of Tl2Hg3Q4 (Q = S, Se, and Te). The incongruently melting Tl2Hg3Q4 crystals were grown in a TlxQ flux. These compounds are isostructural and crystallize in a monoclinic cell with a layered structure, adopting the space group C2/c with a = 11.493(2) Å, b = 6.6953(13) Å, c = 12.937(3) Å, β = 114.98(3)° for Tl2Hg3S4, a = 11.977(2) Å, b = 6.9264(14) Å, c = 13.203(3) Å, β = 116.36(3)° for Tl2Hg3Se4 and a = 12.648(3) Å, b = 7.3574(15) Å, c = 13.701(3) Å, β = 117.48(3)° for Tl 2Hg3Te4. The structures feature infinite chains of [Hg3Q4]2-, which are linked into layers by charge balancing Tl atoms. The compounds have very high densities (>8.3 g/cm3) with experimentally determined band gaps of 2.05, 1.57, and 0.90 eV for Q = S, Se, and Te, respectively. Using the refined crystal structures, we performed detailed band structure calculations at the density functional theory (DFT) level, using the screened-exchange local density approximation (sx-LDA). The results indicate that the compounds are semiconductors with the sulfur analog, having an indirect band gap, and the selenium and tellurium analogs, having direct energy band gaps. There is strong Hg 6s and Tl 6p orbital character in the conduction band minimum, while the valence band maximum has predominantly chalcogen p state character mixed in with a Tl 6s contribution. The band structure calculations support the experimental observation of a narrowing of the band gap in the series Q = S, Se, and Te, which results from the increasing extension of the outermost chalcogen p orbitals.
KW - cadmium telluride
KW - chalcogenide
KW - crystal growth
KW - X-ray detector
UR - http://www.scopus.com/inward/record.url?scp=80053532635&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=80053532635&partnerID=8YFLogxK
U2 - 10.1021/cm2019857
DO - 10.1021/cm2019857
M3 - Article
AN - SCOPUS:80053532635
VL - 23
SP - 4375
EP - 4383
JO - Chemistry of Materials
JF - Chemistry of Materials
SN - 0897-4756
IS - 19
ER -