Abstract
We report the synthesis, physical characterization, and crystal growth of Tl4CdI6. We show that this material has good photoconductivity and is a promising semiconductor for room temperature X-ray and γ-ray detection. Large single crystals were grown by the vertical Bridgman method and cut to dimensions appropriate for detector testing. Single crystal X-ray diffraction refinements confirm that Tl4CdI6 crystallizes in the tetragonal crystal system with a centrosymmetric space group of P4/mnc, with a calculated density of 6.87 g/cm3. Thermal analysis and high-temperature synchrotron powder diffraction studies were used to determine phase relationships and crystallization behavior during crystal growth. We have elucidated the reason for different colors encountered when synthesizing or growing single crystals of Tl4CdI6 (yellow, red, and black), and it is the presence of a small amount of TlI impurity. We report proper crystal growth conditions to obtain essentially pure yellow Tl4CdI6 crystals. The material having the yellow color has a band gap of 2.8 eV. First-principles density functional theory calculations indicate a direct band gap at the point of the Brillouin zone. The Tl4CdI6 crystals have a resistivity of 1010 ω·cm. Photoconductivity measurements on the as-grown crystals show mobility-lifetime product on the order of 10-4 cm2/V for both electrons and holes. The promising detector properties of this material are confirmed by preliminary measurements showing a clear spectral response to an Ag X-ray source, which classifies Tl4CdI6 as an emerging material for radiation detection.
| Original language | English |
|---|---|
| Pages (from-to) | 2401-2410 |
| Number of pages | 10 |
| Journal | Crystal Growth and Design |
| Volume | 14 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - May 7 2014 |
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ASJC Scopus subject areas
- Chemistry(all)
- Materials Science(all)
- Condensed Matter Physics
Cite this
Crystal growth of Tl4CdI6 : A wide band gap semiconductor for hard radiation detection. / Wang, Shichao; Liu, Zhifu; Peters, John A.; Sebastian, Maria; Nguyen, Sandy L.; Malliakas, Christos D.; Stoumpos, Constantinos C.; Im, Jino; Freeman, Arthur J; Wessels, Bruce W.; Kanatzidis, Mercouri G.
In: Crystal Growth and Design, Vol. 14, No. 5, 07.05.2014, p. 2401-2410.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Crystal growth of Tl4CdI6
T2 - A wide band gap semiconductor for hard radiation detection
AU - Wang, Shichao
AU - Liu, Zhifu
AU - Peters, John A.
AU - Sebastian, Maria
AU - Nguyen, Sandy L.
AU - Malliakas, Christos D.
AU - Stoumpos, Constantinos C.
AU - Im, Jino
AU - Freeman, Arthur J
AU - Wessels, Bruce W.
AU - Kanatzidis, Mercouri G
PY - 2014/5/7
Y1 - 2014/5/7
N2 - We report the synthesis, physical characterization, and crystal growth of Tl4CdI6. We show that this material has good photoconductivity and is a promising semiconductor for room temperature X-ray and γ-ray detection. Large single crystals were grown by the vertical Bridgman method and cut to dimensions appropriate for detector testing. Single crystal X-ray diffraction refinements confirm that Tl4CdI6 crystallizes in the tetragonal crystal system with a centrosymmetric space group of P4/mnc, with a calculated density of 6.87 g/cm3. Thermal analysis and high-temperature synchrotron powder diffraction studies were used to determine phase relationships and crystallization behavior during crystal growth. We have elucidated the reason for different colors encountered when synthesizing or growing single crystals of Tl4CdI6 (yellow, red, and black), and it is the presence of a small amount of TlI impurity. We report proper crystal growth conditions to obtain essentially pure yellow Tl4CdI6 crystals. The material having the yellow color has a band gap of 2.8 eV. First-principles density functional theory calculations indicate a direct band gap at the point of the Brillouin zone. The Tl4CdI6 crystals have a resistivity of 1010 ω·cm. Photoconductivity measurements on the as-grown crystals show mobility-lifetime product on the order of 10-4 cm2/V for both electrons and holes. The promising detector properties of this material are confirmed by preliminary measurements showing a clear spectral response to an Ag X-ray source, which classifies Tl4CdI6 as an emerging material for radiation detection.
AB - We report the synthesis, physical characterization, and crystal growth of Tl4CdI6. We show that this material has good photoconductivity and is a promising semiconductor for room temperature X-ray and γ-ray detection. Large single crystals were grown by the vertical Bridgman method and cut to dimensions appropriate for detector testing. Single crystal X-ray diffraction refinements confirm that Tl4CdI6 crystallizes in the tetragonal crystal system with a centrosymmetric space group of P4/mnc, with a calculated density of 6.87 g/cm3. Thermal analysis and high-temperature synchrotron powder diffraction studies were used to determine phase relationships and crystallization behavior during crystal growth. We have elucidated the reason for different colors encountered when synthesizing or growing single crystals of Tl4CdI6 (yellow, red, and black), and it is the presence of a small amount of TlI impurity. We report proper crystal growth conditions to obtain essentially pure yellow Tl4CdI6 crystals. The material having the yellow color has a band gap of 2.8 eV. First-principles density functional theory calculations indicate a direct band gap at the point of the Brillouin zone. The Tl4CdI6 crystals have a resistivity of 1010 ω·cm. Photoconductivity measurements on the as-grown crystals show mobility-lifetime product on the order of 10-4 cm2/V for both electrons and holes. The promising detector properties of this material are confirmed by preliminary measurements showing a clear spectral response to an Ag X-ray source, which classifies Tl4CdI6 as an emerging material for radiation detection.
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U2 - 10.1021/cg5001446
DO - 10.1021/cg5001446
M3 - Article
VL - 14
SP - 2401
EP - 2410
JO - Crystal Growth and Design
JF - Crystal Growth and Design
SN - 1528-7483
IS - 5
ER -