Electroreflectance: A Status Report

Electroabsorption Spectroscopy Measurements of the Exciton Binding Energy, Electron–Hole Reduced Effective Mass, and Band Gap in the Perovskite CH3NH3PbI3

“…It has been shown both theoretically, through a “contact exciton” model, , and experimentally, through extensive electroreflectance studies on Ge, , that in the limit where the bound states of the exciton are effectively “mixed” with the continuum it is possible to describe Wannier exciton effects in the χ (3) EA response using low-field FKA theory. In this limit, the EA response can be thought of largely in terms of the modulation of a Coulomb-modified continuum of states, , and one can replace ϵ­( E ,0) in eq with a model dielectric function for a Wannier exciton. , The “mixing” of the exciton-bound states with the continuum in zero applied field is due to the ionization of bound states caused by excitonic interband scattering phenomena resulting from interactions between excitons and LO-phonons or by field ionization due to microscopic heterogeneity in the electrostatic potential energy surface from charged impurity sites within the polycrystalline sample . To a first approximation, these ionization effects result in a homogeneous broadening of the exciton line width that can be modeled by a phenomenological parameter Γ when Elliott’s function is used for ϵ­( E ,0).…”

Franz-keldysh effect in emission of electroluminescent ZnS:Cu, Cl films

“…The Franz-Keldysh effect in absorption resulting from interband transitions (1) is well studied for a number of semiconductors (2,3). Yet there are only some reports' about the Franz-Keldysh effect in radiative transitions involving band states (4 to 7 ) .…”