Advancements in CdZnTe Detectors: Overcoming Challenges Through Physical and Digital Correction Techniques

Cadmium zinc telluride (CdZnTe, CZT), a high-atomic number (high-Z) semiconductor material, distinguishes itself from equivalents with its wide bandgap, superior electronic transport properties, high material density, and atomic numbers for high-resolution detection of gamma rays at room temperature. Room-temperature CZT detectors find application in medical imaging systems (single-photon emission computed tomography (SPECT) and positron emission tomography (PET)), radiation detection for security and homeland defense, environmental monitoring, X-ray astronomy, and high-energy physics experiments. Despite their success, CZT detectors encounter challenges, notably poor hole-transport properties and crystal growth yield. These limitations stem from crystal imperfections, charge trapping in defect centers, and compositional inhomogeneity. This chapter elucidates both physical and digital correction schemes employed to address these challenges and compensate for their effects in CZT detectors. Physical solutions, such as virtual Frisch grid configurations (small pixel geometry, Frisch collar, or coplanar grid configurations), effectively transform CZT detectors into single-polarity devices. On the other hand, digital data-processing solutions, such as biparametric correlation, offer postdetection corrections to counteract charge-trapping effects. This chapter provides a comprehensive overview, reviewing various aspects of physical and digital mitigation techniques to overcome limitations in advanced CZT room-temperature radiation detectors. The insights gained pave the way for enhanced applications in medical imaging, border security, nuclear nonproliferation, and beyond, marking a significant stride in the evolution of radiation detection technology.