[21p-H137-1~22] 7.2 Applications and technologies of electron beams

△ [21p-H137-16] Gamma-ray tolerance of CdTe photodiode for radiation tolerant FEA image sensor

〇Tomoya Igari¹, Joe Koguchi¹, Tamotsu Okamoto¹, Yasuhito Gotoh², Nobuhiro Sato², Masafumi Akiyoshi³, Ikuji TAKAGI² (1.NIT, Kisarazu Coll., 2.Kyoto Univ., 3.Osaka Pref. Univ.)

Keywords:CdTe,II-VI compounds,field emitter array

The effect of gamma irradiation on two types (superstrate- and substrate-type) of CdS/CdTe photodiodes, which we have proposed as potential photoconducting films for compact image sensors with a field emitter array (FEA), was investigated. A ⁶⁰Co gamma-ray source was employed, and the total gamma irradiation dose was more than 1 MGy. For the superstrate-type structure, the irradiation caused the short-circuit current density (J_SC) to decrease, probably due to the resulting decreased transmittance of the glass substrate. On the other hand, little degradation of the I-V characteristics or spectral response was observed after the gamma irradiation for the substrate-type structure. These results suggest that, taking into account the decrease in transmittance of the glass substrate, the CdS/CdTe photodiodes have sufficient tolerance to high gamma-ray exposure.