  Study of the local optical properties using electron beam (e-beam) can
provide a valuable information concerning the inspection of the materials
quality, the presence of the different phase inclusions and defects. Halide
perovskites have been shown to be highly sensitive to external stress
conditions like ambient atmosphere, light, and heat. In this paper, the
cathodoluminescence (CL) spectroscopy has been exploited to carry out the
investigation of CH3NH3PbBr3 monocrystals under low energy electron beam
irradiation. The CL spectra exhibited strong transformation with the increase
of the irradiation dose and significant shifts of the peak maximums from 2.23
eV to >2.5 eV. Utilizing a larger e-beam energy (>20 keV) was found to be
preferable to slow down the dynamics of the decomposition and corrosion. The
mechanisms of the changes in MAPbBr3 properties after e-beam exposure and
correlation to the in-depth distribution of deposited energy were discussed.
