We present a method to separate coherent and incoherent contributions to cathodoluminescence from bulk materials by using angle-resolved cathodoluminescence spectroscopy. Using 5 and 30 keV electrons, we measure the cathodoluminescence spectra for Si, GaAs, Al, Ag, Au, and Cu and determine the angular emission distributions for Al, GaAs, and Si. Aluminium shows a clear dipolar radiation profile due to coherent transition radiation, while GaAs shows incoherent luminescence characterized by a Lambertian angular distribution. Silicon shows both transition radiation and incoherent radiation. From the angular data, we determine the ratio between the two processes and decompose their spectra. This method provides a powerful way to separate different radiative cathodoluminescence processes, which is useful for material characterization and in studies of electron- and light-matter interaction in metals and semiconductors.

E.C. Garnett (Erik)
J. Appl. Phys.
Photonic Materials

Brenny, B., Coenen, T., & Polman, A. (2014). Quantifying coherent and incoherent cathodoluminescence in semiconductors and metals. J. Appl. Phys., 115(24, Article number: 244307), 1–7. doi:10.1063/1.4885426