cadmium zinc telluride
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. The band gap varies from approximately 1.4 to 2.2 eV, depending on composition.{{cite book |first1=Peter |last1=Capper |title=Properties of Narrow Gap Cadmium-based Compounds |pages=618 |publisher=INSPEC |isbn=0-85296-880-9 |year=1994}}
Characteristics
File:YanDavos_on_SPOT.jpg quadruped robot for radiation mapping in the Chernobyl Exclusion Zone]]
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 detectors.{{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 }} CZT can be formed into different shapes for different radiation-detecting applications, and a variety of electrode geometries, such as coplanar grids {{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/}} and small pixel detectors,{{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 |page=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}} have been developed to provide unipolar (electron-only) operation, thereby improving energy resolution. 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.{{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 }} Pixelated CZT with a volume of 6 cm3 can achieve 0.71% FWHM energy resolution at 662 keV and perform Compton imaging.{{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 }}
See also
References
{{Reflist}}
External links
- [https://web.archive.org/web/20061210213049/http://www.npi.gov.au/database/substance-info/profiles/17.html National Pollutant Inventory - Cadmium and compounds]
{{cadmium compounds}}
{{zinc compounds}}
{{Tellurides}}
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Category:Nonlinear optical materials