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 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−2</sup> 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 xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <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 xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <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.