Towards direct coupling of perovskite single crystals to Topmetal CMOS pixel charge sensors using epoxy adhesive for high-resolution radiation imaging

Abstract

We present a study using epoxy adhesive to directly couple perovskite single crystals to Topmetal CMOS pixel charge sensors. Topmetal-II ^- is a low-noise integrated pixel sensor with a 72×72 pixel array of 83.2 μm pitch, capable of directly collecting external charge through exposed metal electrodes in the topmost metal layer. The proposed coupling layer is formed by mixing pure epoxy resin and hardener in different proportions, which exhibits both good electrical and mechanical strength to perovskite single crystals due to its tunable resistivity ranging from 1×10⁸ Ω cm to 5×10¹² Ω cm, long-term stability, and strong bonding strength. We successfully bonded Topmetal-II ^- sensors to two types of perovskite single crystals to form hybrid device prototypes using this method and demonstrated its potential applications for high-spatial-resolution imaging, particularly in X-ray imaging.