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Sensitive and Fast Direct Conversion X‐Ray Detectors Based on Single‐Crystalline HgI 2 Photoconductor and ZnO Nanowire Vacuum Diode
Author(s) -
Zhang Zhipeng,
Zhang Zhaojun,
Zheng Wei,
Wang Kai,
Chen Huanjun,
Deng Shaozhi,
Huang Feng,
Chen Jun
Publication year - 2020
Publication title -
advanced materials technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.184
H-Index - 42
ISSN - 2365-709X
DOI - 10.1002/admt.201901108
Subject(s) - x ray detector , detector , nanowire , optoelectronics , diode , materials science , photoconductivity , cathode , crystallite , x ray , optics , physics , electrical engineering , metallurgy , engineering
Photoconductive cold cathode X‐ray detectors are highly promising for use in medical diagnosis, industrial inspection, and scientific research applications. However, development of highly sensitive, fast, and stable direct conversion X‐ray detectors remains very challenging because of structural and material limitations. This article presents a direct conversion X‐ray detector based on a HgI 2 crystal and a ZnO nanowire vacuum diode with sensitivity of 6.8 × 10 3 µCGy air −1 cm −2 , which is nearly two orders of magnitude higher than that of a commercial a‐Se X‐ray detector. The X‐ray detector, which uses a high‐crystallization HgI 2 photoconductor, shows a response time of 0.24 ms, thus significantly outperforming the polycrystalline HgI 2 X‐ray detector. In addition, the current limitation between the HgI 2 photoconductor and the ZnO nanowire cold cathodes guaranteed device reliability under high applied electric fields for practical applications. The findings presented in this work demonstrate that the proposed X‐ray detector based on the HgI 2 photoconductor and the ZnO nanowire vacuum diode is highly efficient and stable.