Valence Band Dispersion Measurements of Perovskite Single Crystal with Angle-resolved Photoemission Spectroscopy

TL;DR

This study used angle-resolved photoemission spectroscopy to measure the valence band dispersion in a perovskite single crystal, providing detailed electronic structure insights relevant for optoelectronic applications.

Contribution

First detailed ARPES measurement of valence band dispersion in CH3NH3PbBr3 single crystal, linking experimental data with theoretical calculations.

Findings

Valence band dispersions of ~0.73 eV and ~0.98 eV along specific directions

Hole effective mass estimated at ~0.59 m0

High surface quality confirmed by AFM and SEM

Abstract

The electronic structure of the cleaved perovskite (CH3NH3PbBr3) single crystal was studied in an ultra-high vacuum (UHV) system by angle-resolved photoemission spectroscopy (ARPES) and inverse photoelectron spectroscopy (IPES). Highly reproducible dispersive features of the valence bands were observed with nice symmetry about the Brillouin zone center and boundaries. The largest dispersion width was found to be ~0.73 eV and ~0.98 eV along the {\Gamma}X and {\Gamma}M directions, respectively. The effective mass of the holes was estimated to be ~0.59 m0. The quality of the surface was verified by atomic force microscopy (AFM) and scanning electron microscope (SEM). The elemental composition was investigated by high resolution x-ray photoelectron spectroscopy (XPS). The experimental electronic structure shows a good agreement with the theoretical calculation.