Abstract
Semiconductor-based direct conversion X-ray sensors have widespread applications spanning from medical diagnosis to industrial inspection. However, current findings on X-ray detection based on perovskites shows high sensitivity but exhibit large leakage current and poor stability, thus, inhibiting them from commercialization. Highly stable AgBiS 2 with large attenuation coefficient (μ = 3.07 g cm −2 at 70 keV), shows excellent charge conversion due to its higher atomic number (Bi, Z = 83), and density (ρ = 7.02 g cm −3 ) was used for X-ray detection. Here, we approach to enhance the net sensitivity of AgBiS 2 by tailoring all three parameters by segregating micro/ nanocrystals of cerium oxide (CeO 2 ) at the AgBiS 2 grain boundary (GB) region. From the X-ray impinged photocurrent response, substantial GB segregation of n-CeO 2 at the AgBiS 2 interface leads to improved attenuation and promotes the conversion of multiple scattered X-ray photons into electrons by interacting with the adjacent grains, thus resulting in enhanced photocurrent generation. The sensitivity (S) and noise equivalent dose (NED) ratio were calculated to determine the lowest detectivity of the sensor with less generated noise signals. From these experimental findings, 10 % of n-CeO 2 segregation leads to an improvement in the sensitivity of AgBiS 2 to 29 μC mGy −1 cm −3 . • X-ray sensors were fabricated with micro/ nano CeO 2 segregated AgBiS 2 thick films. • Multiple scattered X-ray photons at the AgBiS 2 grain boundary region were effectively utilized by nano CeO 2 grains, resulting in higher charge carrier generation. • X-ray impinged photocurrent measurement revealed nano CeO 2 :AgBiS 2 presents record sensitivity 29.3 μC mGy −1 cm −3 for 7.97 mGy dose.
Published Version
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