{{Short description|Metal alloy}}
{{Short description|Metal alloy}}
”’Cadmium zinc telluride”’, (CdZnTe) or ”’CZT”’, is a compound of [[cadmium]], [[zinc]] and [[tellurium]] or, more strictly speaking, an alloy of [[cadmium telluride]] and [[zinc telluride]]. A [[direct bandgap]] [[semiconductor]], it is used in a variety of applications, including [[Semiconductor detector|semiconductor radiation detectors]], [[photorefraction|photorefractive]] gratings, [[electro-optic modulator]]s, [[solar cell]]s, and [[Terahertz radiation|terahertz]] generation and detection.<ref name=”bbc_czt”>{{Cite web |date=2025-12-12 |title=”It”s amazing’ – the wonder material very few can make |url=https://www.bbc.com/news/articles/c24l223d9n7o |access-date=2025-12-12 |website=www.bbc.com |language=en-GB}}</ref> The band gap varies from approximately 1.4 to 2.2 [[electronvolt|eV]], depending on composition.<ref>{{cite book |first1=Peter |last1=Capper |title=Properties of Narrow Gap Cadmium-based Compounds |page=618 |publisher=INSPEC |isbn=0-85296-880-9 |year=1994}}</ref>
”’Cadmium zinc telluride”’, (CdZnTe) or ”’CZT”’, is a compound of [[cadmium]], [[zinc]] and [[tellurium]] or, more strictly speaking, an alloy of [[cadmium telluride]] and [[zinc telluride]]. A [[direct bandgap]] [[semiconductor]], it is used in a variety of applications, including [[Semiconductor detector|semiconductor radiation detectors]], [[photorefraction|photorefractive]] gratings, [[electro-optic modulator]]s, [[solar cell]]s, and [[Terahertz radiation|terahertz]] generation and detection.<ref name=”bbc_czt”>{{Cite web |date=2025-12-12 |title=”It”s amazing’ – the wonder material very few can make |url=https://www.bbc.com/news/articles/c24l223d9n7o |access-date=2025-12-12 |website=www.bbc.com |language=en-GB}}</ref>
== Characteristics ==
== Characteristics ==
[[File:Cs137Spectra.tif|thumb|A Cs-137 gamma-ray spectrum collected using an M400 pixelated CZT imaging spectrometer. Energy resolution, as measured by full-width-at-half-maximum (FWHM), is better than 1%.]]
[[File:Cs137Spectra.tif|thumb|A Cs-137 gamma-ray spectrum collected using an M400 pixelated CZT imaging spectrometer. Energy resolution, as measured by full-width-at-half-maximum (FWHM), is better than 1%.]]
Radiation detectors using CZT can operate in direct-conversion (or photoconductive) mode at room temperature, unlike some other materials (particularly [[germanium]]) which require cooling. Their relative advantages include high sensitivity for X-rays and gamma rays, due to the high atomic numbers of Cd and Te, and better energy resolution than [[Scintillator|scintillator detectors]].<ref>{{cite journal|title=Small pixel CZT detector for hard X-ray spectroscopy|journal=Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | doi=10.1016/j.nima.2011.01.144 | volume=652|pages=158–161|year=2011 |last1=Wilson |first1=Matthew David |last2=Cernik |first2=Robert |last3=Chen |first3=Henry |last4=Hansson |first4=Conny |last5=Iniewski |first5=Kris |last6=Jones |first6=Lawrence L. |last7=Seller |first7=Paul |last8=Veale |first8=Matthew C. |issue=1 |bibcode=2011NIMPA.652..158W }}</ref> CZT can be formed into different shapes for different radiation-detecting applications, and a variety of electrode geometries, such as coplanar grids <ref>{{Cite journal|year=1995|title=Unipolar charge sensing with coplanar electrodes –– application to semiconductor detectors|journal=[[IEEE Transactions on Nuclear Science]]|volume=42|issue=4|pages=207–213|doi=10.1109/23.467848|last1=Luke|first1=P.N.|bibcode=1995ITNS…42..207L |s2cid=64754800 |url=https://digital.library.unt.edu/ark:/67531/metadc684991/}}</ref> and [[HEXITEC|small pixel]] detectors,<ref>{{cite journal|title=Pixellated Cd(Zn)Te high–energy X–ray instrument|journal= Journal of Instrumentation| doi=10.1088/1748–0221/6/12/C12009 |pmid=22737179 | volume=6|issue=12 |article-number=C12009|pmc=3378031|year=2011 |last1=Seller |first1=P. |last2=Bell |first2=S. |last3=Cernik |first3=R. J. |last4=Christodoulou |first4=C. |last5=Egan |first5=C. K. |last6=Gaskin |first6=J. A. |last7=Jacques |first7=S. |last8=Pani |first8=S. |last9=Ramsey |first9=B. D. |last10=Reid |first10=C. |last11=Sellin |first11=P. J. |last12=Scuffham |first12=J. W. |last13=Speller |first13=R. D. |last14=Wilson |first14=M. D. |last15=Veale |first15=M. C. |bibcode= 2011JInst…6C2009S}}</ref> have been developed to provide unipolar (electron-only) operation, thereby improving energy resolution. A 1 cm<sup>3</sup> CZT crystal has a sensitivity range of 30 keV to 3 MeV with a 2.5% [[Full Width at Half Maximum|FWHM]] energy resolution at 662 keV.<ref>{{cite journal |first1=Yannick |last1=Verbelen |first2=Peter G. |last2=Martin |first3=Kamran |last3=Ahmad |first4=Suresh |last4=Kaluvan |first5=Thomas B. |last5=Scott |title=Miniaturised Low-Cost Gamma Scanning Platform for Contamination Identification, Localisation and Characterisation: A New Instrument in the Decommissioning Toolkit |doi=10.3390/s21082884 |pmc=8074328 |doi-access=free |journal=Sensors |volume=21 |issue=8 |year=2021|page=2884 |pmid=33924123 |bibcode=2021Senso..21.2884V }}</ref> Pixelated CZT with a volume of 6 cm<sup>3</sup> can achieve 0.71% [[Full Width at Half Maximum|FWHM]] energy resolution at 662 keV and perform [[Compton telescope|Compton imaging]].<ref>{{cite journal |first1=Feng|last1=Zhang |first2=Cedric |last2=Herman |first3=Zhong |last3=He |first4=Gianluigi |last4=De Geronimo |first5=Emerson |last5=Vernon |first6=Jack |last6=Fried |title=Characterization of the H3D ASIC Readout System and 6.0 cm³ 3-D Position Sensitive CdZnTe Detectors |journal=IEEE Transactions on Nuclear Science |volume=59 |issue=1 |year=2012|page=236 |doi=10.1109/TNS.2011.2175948 |bibcode=2012ITNS…59..236Z |s2cid=16381112 }}</ref>
CZT [[]], .<ref>{{cite |= |last1= |= of – |= |= |=— |year=}}</ref> A 1 cm<sup>3</sup> CZT crystal has a sensitivity range of 30 keV to 3 MeV with a 2.5% [[Full Width at Half Maximum|FWHM]] energy resolution at 662 keV.<ref>{{cite journal |first1=Yannick |last1=Verbelen |first2=Peter G. |last2=Martin |first3=Kamran |last3=Ahmad |first4=Suresh |last4=Kaluvan |first5=Thomas B. |last5=Scott |title=Miniaturised Low-Cost Gamma Scanning Platform for Contamination Identification, Localisation and Characterisation: A New Instrument in the Decommissioning Toolkit |doi=10.3390/s21082884 |pmc=8074328 |doi-access=free |journal=Sensors |volume=21 |issue=8 |year=2021|page=2884 |pmid=33924123 |bibcode=2021Senso..21.2884V }}</ref> Pixelated CZT with a volume of 6 cm<sup>3</sup> can achieve 0.71% [[Full Width at Half Maximum|FWHM]] energy resolution at 662 keV and perform [[Compton telescope|Compton imaging]].<ref>{{cite journal |first1=Feng|last1=Zhang |first2=Cedric |last2=Herman |first3=Zhong |last3=He |first4=Gianluigi |last4=De Geronimo |first5=Emerson |last5=Vernon |first6=Jack |last6=Fried |title=Characterization of the H3D ASIC Readout System and 6.0 cm³ 3-D Position Sensitive CdZnTe Detectors |journal=IEEE Transactions on Nuclear Science |volume=59 |issue=1 |year=2012|page=236 |doi=10.1109/TNS.2011.2175948 |bibcode=2012ITNS…59..236Z |s2cid=16381112 }}</ref>
== Applications==
Radiation detectors using CZT can operate in direct-conversion (or photoconductive) mode at room temperature, unlike some other materials (particularly [[germanium]]) which require cooling or technologies that require a [[photomultiplier tube]].<ref name=”DIC”>{{cite news |title=GE Healthcare Acquires CZT Detector Company |url=https://www.dicardiology.com/content/ge-healthcare-acquires-czt-detector-company |access-date=16 December 2025 |publisher=Diagnostic and Intervention Cardiology |date=15 November 2010}}</ref> Their relative advantages include high sensitivity for X-rays and gamma rays, due to the high atomic numbers of Cd and Te, and better energy resolution than [[Scintillator|scintillator detectors]].<ref>{{cite journal|title=Small pixel CZT detector for hard X-ray spectroscopy|journal=Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | doi=10.1016/j.nima.2011.01.144 | volume=652|pages=158–161|year=2011 |last1=Wilson |first1=Matthew David |last2=Cernik |first2=Robert |last3=Chen |first3=Henry |last4=Hansson |first4=Conny |last5=Iniewski |first5=Kris |last6=Jones |first6=Lawrence L. |last7=Seller |first7=Paul |last8=Veale |first8=Matthew C. |issue=1 |bibcode=2011NIMPA.652..158W }}</ref> This allows for reduced radiation dosagd, reduced data acquisition time, and small instruments.<ref name=”DIC” /><ref>{{cite news |last1=Fornell |first1=Dave |title=Nuclear Imaging Moves Toward Digital Detector Technology |url=https://www.dicardiology.com/article/nuclear-imaging-moves-toward-digital-detector-technology |access-date=16 December 2025 |publisher=Diagnostic and Interventional Cardiology |date=15 June 2018}}</ref>
CZT can be formed into different shapes for different radiation-detecting applications, and a variety of electrode geometries, such as coplanar grids <ref>{{Cite journal|year=1995|title=Unipolar charge sensing with coplanar electrodes — application to semiconductor detectors|journal=[[IEEE Transactions on Nuclear Science]]|volume=42|issue=4|pages=207–213|doi=10.1109/23.467848|last1=Luke|first1=P.N.|bibcode=1995ITNS…42..207L |s2cid=64754800 |url=https://digital.library.unt.edu/ark:/67531/metadc684991/}}</ref> and [[HEXITEC|small pixel]] detectors,<ref>{{cite journal|title=Pixellated Cd(Zn)Te high-energy X-ray instrument|journal= Journal of Instrumentation| doi=10.1088/1748-0221/6/12/C12009 |pmid=22737179 | volume=6|issue=12 |article-number=C12009|pmc=3378031|year=2011 |last1=Seller |first1=P. |last2=Bell |first2=S. |last3=Cernik |first3=R. J. |last4=Christodoulou |first4=C. |last5=Egan |first5=C. K. |last6=Gaskin |first6=J. A. |last7=Jacques |first7=S. |last8=Pani |first8=S. |last9=Ramsey |first9=B. D. |last10=Reid |first10=C. |last11=Sellin |first11=P. J. |last12=Scuffham |first12=J. W. |last13=Speller |first13=R. D. |last14=Wilson |first14=M. D. |last15=Veale |first15=M. C. |bibcode= 2011JInst…6C2009S}}</ref> have been developed to provide unipolar (electron-only) operation, thereby improving energy resolution.
== Production ==
== Production ==
Metal alloy
Cadmium zinc telluride, (CdZnTe) or CZT, is a compound of cadmium, zinc and tellurium or, more strictly speaking, an alloy of cadmium telluride and zinc telluride. A direct bandgap semiconductor, it is used in a variety of applications, including semiconductor radiation detectors, photorefractive gratings, electro-optic modulators, solar cells, and terahertz generation and detection.[1]
The CZT band gap varies from approximately 1.4 to 2.2 eV, depending on composition.[2] A 1 cm3 CZT crystal has a sensitivity range of 30 keV to 3 MeV with a 2.5% FWHM energy resolution at 662 keV.[3] Pixelated CZT with a volume of 6 cm3 can achieve 0.71% FWHM energy resolution at 662 keV and perform Compton imaging.[4]
Radiation detectors using CZT can operate in direct-conversion (or photoconductive) mode at room temperature, unlike some other materials (particularly germanium) which require cooling or technologies that require a photomultiplier tube.[5] Their relative advantages include high sensitivity for X-rays and gamma rays, due to the high atomic numbers of Cd and Te, and better energy resolution than scintillator detectors.[6] This allows for reduced radiation dosagd, reduced data acquisition time, and small instruments.[5][7]
CZT can be formed into different shapes for different radiation-detecting applications, and a variety of electrode geometries, such as coplanar grids [8] and small pixel detectors,[9] have been developed to provide unipolar (electron-only) operation, thereby improving energy resolution.
Monocrystalline CZT is produced by only a few companies worldwide, with demand exceeding supply in 2025.[1] Furthermore, China placed export controls on CZT in 2025.[10] Consequently, some projects may recycle CZT from other equipment, or use the cadmium telluride as a substitute.[1]
- ^ a b c “‘It’s amazing’ – the wonder material very few can make”. www.bbc.com. 2025-12-12. Retrieved 2025-12-12.
- ^ Capper, Peter (1994). Properties of Narrow Gap Cadmium-based Compounds. INSPEC. p. 618. ISBN 0-85296-880-9.
- ^ Verbelen, Yannick; Martin, Peter G.; Ahmad, Kamran; Kaluvan, Suresh; Scott, Thomas B. (2021). “Miniaturised Low-Cost Gamma Scanning Platform for Contamination Identification, Localisation and Characterisation: A New Instrument in the Decommissioning Toolkit”. Sensors. 21 (8): 2884. Bibcode:2021Senso..21.2884V. doi:10.3390/s21082884. PMC 8074328. PMID 33924123.
- ^ Zhang, Feng; Herman, Cedric; He, Zhong; De Geronimo, Gianluigi; Vernon, Emerson; Fried, Jack (2012). “Characterization of the H3D ASIC Readout System and 6.0 cm³ 3-D Position Sensitive CdZnTe Detectors”. IEEE Transactions on Nuclear Science. 59 (1): 236. Bibcode:2012ITNS…59..236Z. doi:10.1109/TNS.2011.2175948. S2CID 16381112.
- ^ a b “GE Healthcare Acquires CZT Detector Company”. Diagnostic and Intervention Cardiology. 15 November 2010. Retrieved 16 December 2025.
- ^ Wilson, Matthew David; Cernik, Robert; Chen, Henry; Hansson, Conny; Iniewski, Kris; Jones, Lawrence L.; Seller, Paul; Veale, Matthew C. (2011). “Small pixel CZT detector for hard X-ray spectroscopy”. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 652 (1): 158–161. Bibcode:2011NIMPA.652..158W. doi:10.1016/j.nima.2011.01.144.
- ^ Fornell, Dave (15 June 2018). “Nuclear Imaging Moves Toward Digital Detector Technology”. Diagnostic and Interventional Cardiology. Retrieved 16 December 2025.
- ^ Luke, P.N. (1995). “Unipolar charge sensing with coplanar electrodes — application to semiconductor detectors”. IEEE Transactions on Nuclear Science. 42 (4): 207–213. Bibcode:1995ITNS…42..207L. doi:10.1109/23.467848. S2CID 64754800.
- ^ Seller, P.; Bell, S.; Cernik, R. J.; Christodoulou, C.; Egan, C. K.; Gaskin, J. A.; Jacques, S.; Pani, S.; Ramsey, B. D.; Reid, C.; Sellin, P. J.; Scuffham, J. W.; Speller, R. D.; Wilson, M. D.; Veale, M. C. (2011). “Pixellated Cd(Zn)Te high-energy X-ray instrument”. Journal of Instrumentation. 6 (12) C12009. Bibcode:2011JInst…6C2009S. doi:10.1088/1748-0221/6/12/C12009. PMC 3378031. PMID 22737179.
- ^ Shaw, Vincent (7 February 2025). “China adds export restrictions for minerals used in thin-film solar”. pv magazine. Retrieved 16 December 2025.
