A Flat Panel Photodetector Formed by a ZnS Photoconductor and ZnO Nanowire Field Emitters Achieving High Responsivity From Ultraviolet to Visible Light for Indirect-Conversion X-Ray Imaging

Flat panel photodetectors have been well studied for their applications in large area detection such as indirect-conversion X-ray imaging. Even though a few of photodetectors have become commercially available, there is still a room for advancement in responsive wavelength range and sensitivity. This paper reports a sensitive broadband flat panel photodetector that integrates a ZnS photoconductor with an array of ZnO nanowire field emitters. The photodetector exhibits a spectral responsivity of 5.93 x 10(2)-3.79 x 10(5) A/W with an external quantum efficiency of 1.03 x 10(5)-134 x 10(6) % from 350 to 700 nm wavelengths. Additionally, a short signal rise time of 55 ms and a fall time of 1.03 s are demonstrated. The flat panel photodetector with broadband detection and a high responsivity shows a great promise for use in indirect-conversion X-ray detector incorporated with a broad range of X-ray scintillators.