Methylammonium Lead Tribromide Single Crystal Detectors towards Robust Gamma-Ray Photon Sensing

In recent years, hybrid perovskite single crystalline solid-state detectors have shown promise in gamma-ray spectroscopy. Here, the gamma-ray photon induced electrical pulses are investigated, which are produced by perovskite solid-state detectors made with the commonly used methylammonium lead tribromide crystals with chlorine incorporation. Under low electric field detector operation, slow pulses generated by gamma-rays with average rise times of 65 mu s are observed, which decreases to 20 mu s when a higher electrical field of 500 V cm(-1) is applied. However, the baseline becomes noisy quickly, which prevents collection of clean pulses for spectra construction. Further, by systematically measuring the temperature dependence and current-voltage characteristics, such instability is attributed to the local ion migration under electrical field creating a fluctuating dark noise, which presents a major challenge in perovskite gamma-ray detector technologies. It is demonstrated that cycling the bias between positive and negative polarity can stabilize the detector, allowing for longer periods of pulse accumulation for generating energy resolved spectra with resolutions of approximate to 35% at 59.6 keV and approximate to 25% at 662 keV at room temperature. The study indicates that the main limiting factors of perovskite-based gamma-ray detectors are slow rise times and bias instability. These challenges must be properly addressed to achieve reproducible, high-resolution gamma-ray detection.