Low temperature cathodoluminescence in organic-inorganic perovskite CH$_3$NH$_3$PbBr$_3$ single crystals

We present the results of the cathodoluminescence study in single crystals of methylammonium lead tribromide CH$_3$NH$_3$PbBr$_3$ in the low temperature orthorhombic phase (temperature range 7–100 K). Near the edge of the optical absorption band, we found a peak at 2.24 eV that exhibited a blue shift with increasing temperature and broad emission centered at 2 eV energy, the position and intensity of which varied with the magnitude of the accelerating voltage and the direction of the electron beam. Based on Monte Carlo modeling, we have shown that for the values of the accelerating voltage used in the experiment, 1100 V and 1300 V, the penetration depth of the electron beam into the sample does not exceed 40 nm. This allows us to conclude that the observed features of the cathodoluminescence spectra are related to the properties of the near-surface layer of the CH$_3$NH$_3$PbBr$_3$ single crystal.