Direct Measurement of Carrier Distribution in Perovskite by Scanning Capacitance Microscopy

This study successfully applies scanning capacitance microscopy (SCM) to organic–inorganic metal halide perovskite materials, providing detailed insights into the microscopic distribution of carrier concentrations and types. We developed and optimized an alumina (Al2O3) insulating layer using atomic layer deposition, with a 5 nm thickness at 398.15 K proving optimal for minimizing defects at the Al2O3/perovskite interface. Further optimizations included selecting an appropriate probe for high-contrast SCM imaging, reducing stray capacitance by scanning at sample edges, and analyzing the effects of light illumination. Our results show that perovskite films with excess PbI2 in the precursor had a more uniform carrier distribution and higher overall carrier concentration. Additionally, we identified distinct p-type and n-type regions in perovskite materials modified with polar molecular additives. This work enables SCM as a robust technique for investigating complex carrier behaviors in perovskite materials.