Theoretical comparison among perovskite, Si and α-Se based X-ray detectors

In recent years, metal halide perovskite materials have received extensive attention due to their strong X-ray absorption capacity, high sensitivity, and low-cost preparation(1). In this work, cesium silver bismuth bromide (Cs2AgBiBr6) perovskite based detectors were simulated by using drift-diffusion equation in Silvaco. The X-ray energy spectrum was calculated according to the open-source TASMICS algorithm provided by J.H. Siewerdsen(2). The perovskite mass energy attenuation coefficients acquired from the NIST database(3) were converted into imaginary parts of material refractive index. According to the simulation results, the average photo-current density of Cs2AgBiBr6 perovskite material is 10(-9)A/cm(2) compared to Si (10(-10)A/cm(2)) and alpha-Se (10(11)/cm(2)). This is due to the relatively large atomic number of Cs2AgBiBr6 material and a high carrier mobility lifetime product. In addition, the Cs2AgBiBr6 photodetector exhibits a high photocurrent-to-dark current ratio (PDR) of 9700 than Si (51), while alpha-Se has the largest PDR value of 1.4301x10(5). In summary, Both Cs2AgBiBr6 and alpha-Se can be used as the ideal direct X-ray detector materials.