Semiconductor Detector Technology for Gamma-Ray Imaging

Semiconductor detectors for gamma-ray imaging exploit wide-band-gap materials to combine high stopping power with room-temperature operation, compact form factors and precise spectroscopic capabilities. Among the leading materials are cadmium zinc telluride (CZT) and cadmium telluride (CdTe), whose high atomic numbers and densities yield excellent detection efficiency for photons in the 50–1 000 keV range. Detectors are commonly fabricated as pixelated arrays bonded to application-specific integrated circuits, enabling simultaneous measurement of photon energy and interaction position. Advances in crystal growth and contact engineering have minimised defects and trapping centres, improving charge transport and energy resolution to below 1 keV full width at half maximum (FWHM) at 60 keV. Recent efforts focus on three-dimensional event reconstruction, mitigation of charge sharing between pixels and the application of machine-learning to characterise material non-uniformities with limited calibration data. These innovations underpin a new generation of gamma-ray cameras for medical diagnostics, nuclear security and astrophysical telescopes, while emerging large-area tiling approaches seek to extend coverage without sacrificing spatial fidelity.

Research from Nature Portfolio

Recent studies have introduced learning-based physical models that integrate principles of charge transport with data-driven parameter estimation to characterise room-temperature semiconductor detectors using minimal calibration measurements. By segmenting detectors into voxels and treating trapping, detrapping and recombination coefficients as trainable parameters, these models infer electron–hole dynamics indirectly from electrode signals. This approach substantially reduces the experimental burden of pixel-by-pixel characterisation, enabling rapid 3D reconstruction of gamma-ray interactions at sub-pixel resolution. Early demonstrations show that such hybrid models can accurately recover mobility–lifetime products and predict spatial non-uniformities, paving the way for real-time monitoring of detector performance in high-flux environments.

Semiconductor Detector Technology for Gamma-Ray Imaging publication trend

The graph below shows the total number of articles in semiconductor detector technology for gamma-ray imaging across all publications each year (not limited to Nature Index journals).

Technical terms

Semiconductor detector: A device using a crystalline semiconductor to convert gamma photons into charge carriers for spectroscopic measurements.

CdZnTe (CZT): A wide-band-gap compound semiconductor offering high density and electron mobility, commonly used for room-temperature gamma-ray detection.

CdTe: Cadmium telluride, a high-atomic-number semiconductor material valued for compact spectrometers and moderate cost.

Pixelation: Division of the detector surface into discrete sensing elements to record interaction position and energy simultaneously.

Energy resolution: The smallest energy difference a detector can distinguish, typically expressed as FWHM of a photopeak.

Charge sharing: The splitting of generated charge carriers between adjacent pixels, which can degrade spectral fidelity if uncorrected.

Schottky contact: A metal–semiconductor junction that forms a rectifying barrier, influencing leakage current and field distribution.

References

1. Research on the Technological Progress of CZT Array Detectors. Sensors (2024).
2. Learning-based physical models of room-temperature semiconductor detectors with reduced data. Scientific Reports (2023).
3. Characterization of the Uniformity of High-Flux CdZnTe Material. Sensors (2020).
4. CdTe X/γ-ray Detectors with Different Contact Materials. Sensors (2021).
5. A 10 cm × 10 cm CdTe Spectroscopic Imaging Detector based on the HEXITEC ASIC. Journal of Instrumentation (2015).
6. Interconnect and bonding techniques for pixelated X-ray and gamma-ray detectors. Journal of Instrumentation (2015).