Electron Microscopy Studies of Non-Local Effects’ Impact on Cathodoluminescence of Semiconductor Laser Structures

Abstract

Spatially and spectrally resolved cathodoluminescence (CL) studies performed in a scanning electron microscope (SEM) or a scanning transmission electron microscope (STEM) are widely applied to determine the luminescence spectrum, map the optical activity and reveal defects in semiconductor structures. It is commonly recognized that the CL signal represents the local properties of the structure region excited by the electron beam. The present investigations show that if the structure under study contains regions with a strong electric field (e.g. p-n junction), the CL signal may much depend on phenomena far from the excitation region. The range of CL-results distortion extends from negligible changes to completely wrong output. It depends on various parameters described in the paper. The CL results obtained for AlGaAs/GaAs laser heterostructures with InGaAs quantum well are presented.