Development of CdTe-based photoelectric conversion layers for radiation tolerant FEA image sensor

Abstract

We proposed a compact image sensor that uses a combination of a matrix-driven Spindt-type field emitter array (FEA) and a CdTe-based photoconducting film. First of all, we investigated the effect of gamma irradiation of CdTe/CdS photodiode for radiation tolerant FEA image sensor. Taking into account the decrease in transmittance of the glass substrate, the CdS/CdTe photodiodes have sufficient tolerance to high gamma-ray exposure more than 1.7 MGy. Next, we investigated I-V characteristics under gamma-ray irradiation. The increase in current due to the gamma-ray absorption was observed. The increase rate in current at the voltage of -5 V was approximately 220 nA/cm² per unit dose rate (1 kGy/h).