Low-noise X-ray PIN photodiodes made of perovskite single crystals by solution-processed dopant incorporated epitaxial growth

Abstract

X-ray photodiodes made of metal halide perovskites (MHPs) which directly convert X-ray photons into electron-hole pairs have shown advantages in low-cost and high X-ray detection sensitivity. However, lattice-mismatched blocking layers deposited by spin-coating or evaporation cannot fully limit the dark current and noise current under large reverse bias. In this work, Solution-processed dopant incorporated epitaxial growth is employed to form sufficient blocking barriers through epitaxially growing lattice-matched n-type MHPs (bismuth-doped) and p-type MHPs (silver-doped) on opposite faces of intrinsic CH3NH3PbBr2.5Cl0.5 MHP single crystals. Through energy structure design, electron/hole blocking layers can form sufficient charges barriers, the X-ray PDs exhibit a low leakage dark current density of ~ 11 nA cm−2 under large reverse electrical field (over 500 V cm−1) and noise current of 47 fAHz−0.5 (1 mm2, over 500 V cm−1). The large external electrical field enables a state-of-art response speed (fall) of 750 ns, large X-ray detection sensitivity of 36.0μCmGy−1cm−2 and the lowest detectable dose rate of 16 nGys−1(40 kVp). This work will motivate new strategies to fabricate high-performance devices based on perovskites using solution-processed methods. These founding also explore a new generation of low dose and high dynamic X-ray detectors based on MHPs.