Pixellated Perovskite Photodiode on IGZO Thin Film Transistor Backplane for Low Dose Indirect X-Ray Detection

Abstract

The integration of perovskite photodetectors with thin-film transistor (TFT) backplane or complementary metal-oxide-semiconductor CMOS circuit is a key step towards prototyping perovskite-based image sensors. Here, we demonstrate a pixel configuration for indirect X-ray detection comprising of IGZO TFTs and perovskite photodiodes (PDs). The perovskite photodiode is patterned by a two-step deposition method. Our integrated TFT/PD pixel shows a weak light detection capability down to 4 nW cm⁻² and a fast-transient response to the pulse light and gate switching. Combining with a CsI scintillator, the integrated pixel achieves a specific X-ray sensitivity of 8.2 <inline-formula> <tex-math notation= LaTeX >$8.2 \\times 10^{2} \\mu \\mathrm{C} \\mathrm{mGy}_{\\text {air }}^{-1} \\mathrm{~cm}^{-3}$ </tex-math></inline-formula>. Theoretically, with a state-of-the-art scintillator, the new pixel can provide a detectable signal for X-ray imaging at a dose rate as low as <inline-formula> <tex-math notation= LaTeX >$10 \\mu \\mathrm{Gy}_{\\text {air }} \\mathrm{s}^{-1}$ </tex-math></inline-formula>. This work provides an advanced pixel design for high resolution, high sensitivity, and high frame-rate flat-panel imager.