Discovering Shared Design Heritage for Semiconductor‐Based Gamma‐Ray Spectrometers: From CdTe to Metal Halide Perovskites

ABSTRACT CdTe‐based compound semiconductors, particularly CdZnTe(CZT), have shaped the technological foundation of room‐temperature gamma‐ray spectrometers through continuous advances in crystal growth, defect control, and device engineering. While metal halide perovskites have recently emerged as promising direct‐conversion materials for gamma‐ray spectroscopy, their performance is consistently evaluated in reference to CZT detectors, reflecting a deeper continuity in device physics and architecture rather than a simple comparison of material properties. This Review examines the parallel evolution of CdTe‐derived and metal halide perovskite gamma‐spectrometers and identifies the shared physical and device‐level principles that underpin high‐resolution spectroscopy. We revisit the historical development of CdTe‐based detectors, highlighting how bandgap engineering, defect suppression, surface passivation, and contact design enabled spectroscopic‐grade operation at room temperature, and analyze how analogous challenges are addressed in perovskite gamma‐spectrometers to achieve intrinsic electrical states, suppress dark current, mitigate defect‐related instabilities, and improve their spectral performance. Across both material platforms, particular emphasis is placed on geometrical device engineering for weighting‐potential control, which emerges as a decisive factor in realizing high energy resolution beyond intrinsic material metrics alone. By consolidating these developments, this Review elucidates a shared design heritage in gamma‐ray spectroscopy technology and provides a rational framework for the development of next‐generation semiconductor‐based gamma‐spectrometers.