Preparation and characterization of free-standing BiI3 single-crystal flakes for X-ray detection application
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Free-standing BiI3 single-crystal flakes with a rhombohedral appearance and 10–100 µm in thickness were prepared by using physical vapor transport method. The (00l) (l = 3, 6, 9, 12) planes of the as-grown crystal present a distribution of layered structure and approximatively atomically smooth surface with 1.3–1.7 nm step height and roughness average 0.38–0.65 nm. Both planar and coplanar electrode configuration devices for X-ray detection were fabricated with the as-grown BiI3 single crystals and the dark resistivity 5.8–6.4 × 1011 Ω cm and 1.2–1.8 × 1011 Ω cm at room temperature were obtained, respectively. A low dark current or high resistivity for planar device is on account of carrier scattering from the I–Bi–I interlayer van der Waals bonding interface. A high net photocurrent and good sensitivity 1.22–1.36 × 104 µC/Gyair/cm2 under X-ray excitation were also obtained with planar device owing to the uniform electric field distribution and high charge collection efficiency.
This work was supported by the NSFC (No. 11675029) and Science and Technology Research Fund of Sichuan Province (Nos. 2016FZ0018 and 2018JY0513).
- 12.M.Z. Kabir, S.O. Kasap, Springer Handbook of Electronic and photonic Materials, Chap. 45, 2nd edn (Springer, New York, 2017), p. 1136Google Scholar