Cadmium zinc telluride

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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]

Contents

Characteristics

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%. Cs137Spectra.tif
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%.

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]

Applications

A YanDavos radiation sensor system based on a 1 cm CZT crystal, deployed on a Boston Dynamics Spot quadruped robot for radiation mapping in the Chernobyl Exclusion Zone YanDavos on SPOT.jpg
A YanDavos radiation sensor system based on a 1 cm CZT crystal, deployed on a Boston Dynamics Spot 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 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.

Production

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]

See also

References

  1. 1 2 3 "'It's amazing' – the wonder material very few can make". www.bbc.com. 2025-12-12. Retrieved 2025-12-12.
  2. ↑ Capper, Peter (1994). Properties of Narrow Gap Cadmium-based Compounds. INSPEC. p. 618. ISBN   0-85296-880-9.
  3. ↑ 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.
  4. ↑ 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.
  5. 1 2 "GE Healthcare Acquires CZT Detector Company". Diagnostic and Intervention Cardiology. 15 November 2010. Retrieved 16 December 2025.
  6. ↑ 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.
  7. ↑ Fornell, Dave (15 June 2018). "Nuclear Imaging Moves Toward Digital Detector Technology". Diagnostic and Interventional Cardiology. Retrieved 16 December 2025.
  8. ↑ 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.
  9. ↑ 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.
  10. ↑ Shaw, Vincent (7 February 2025). "China adds export restrictions for minerals used in thin-film solar". pv magazine. Retrieved 16 December 2025.
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