Application of a ZnO UV sensor for a scintillation-type radiation detector

Radiation detection characteristics of a device combining a YAP:Ce (cerium-doped yttrium aluminum perovskite) scintillator and a ZnO UV sensor were studied using X-ray radiation. Both ZnO and YAP have high resistance to radiation. A photoconductive-type UV sensor with comb-shaped Al electrodes with a gap of 50 μm was fabricated on the Zn-face of a nitrogen-doped ZnO single crystal. A photocurrent spectrum of the ZnO UV sensor showed a peak at wavelength of about 370 nm, and the sensor did not show a response in wavelengths of the visible light region. Scintillation characteristics of YAP:Ce were investigated under the condition of X-ray radiation. Scintillation luminescence of YAP:Ce showed a spectrum with a peak at a wavelength of about 360 nm, which almost corresponds to the peak wavelength of a photocurrent spectrum of the ZnO UV sensor. A device having a structure in which the YAP:Ce scintillator is placed above the ZnO UV sensor was fabricated. When the YAP:Ce scintillator was irradiated by X-rays, the photocurrent of the ZnO UV sensor was proportional to the X-ray intensity. The sensitivity of the device was improved by deposition of a reflective Al film on the YAP:Ce scintillator. The device using the combination of a YAP:Ce scintillator and a ZnO UV sensor can be used as a radiation detector with high radiation resistance.