Photonics Research, Volume. 9, Issue 12, 2420(2021)
Sensitive direct-conversion X-ray detectors formed by ZnO nanowire field emitters and β-Ga2O3 photoconductor targets with an electron bombardment induced photoconductivity mechanism
Fig. 1. Comparison of conceptual design of X-ray detectors and corresponding X-ray response mechanism. (a) Conventional X-ray detectors with TFT readout. (b) Proposed X-ray detectors with vacuum FEA readout.
Fig. 2. Implementation and characterizations of the X-ray detectors. (a) Schematic layout of the vacuum cold cathode X-ray detector. (b) Actual picture of the fabricated X-ray detector. (c) Arrays of patterned ZnO NWs (top image) and cross-sectional view of ZnO NWs (bottom image). (d) Field emission
Fig. 3. Detection performance and operation principle of the proposed X-ray detector. (a), (b) Dark current and photocurrent of the X-ray detector at low and high electric fields. (c) F-N curves of the dark current and photocurrent. (d)–(f) Schematic of the operation principle of X-ray detector at different applied electric fields. (g) The detection sensitivity versus applied electric field curves of the X-ray detector. (h) Internal gain versus electric field curve of the detector under X-ray illumination with the X-ray tube voltage of 6 kV and the X-ray tube current of 0.6 mA. (i) The detection sensitivity versus X-ray tube voltage curves of the X-ray detector with inset showing the theoretical determination of detector sensitivity as a function of X-ray energy. (The experimental value was measured using a DC X-ray tube without beam filters.)
Fig. 4. Temporal response of the X-ray detector. (a)–(c) Time-dependent photocurrent of the X-ray detector with pulsed X-ray source on and off at
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Zhipeng Zhang, Manni Chen, Xinpeng Bai, Kai Wang, Huanjun Chen, Shaozhi Deng, Jun Chen. Sensitive direct-conversion X-ray detectors formed by ZnO nanowire field emitters and β-Ga2O3 photoconductor targets with an electron bombardment induced photoconductivity mechanism[J]. Photonics Research, 2021, 9(12): 2420
Category: Optoelectronics
Received: Jul. 22, 2021
Accepted: Oct. 14, 2021
Published Online: Nov. 12, 2021
The Author Email: Jun Chen (stscjun@mail.sysu.edu.cn)