Luminescence and superradiance in electron-beam-excited <i>AlxGa</i>1−<i>x</i> <i>N</i>

Abstract

Luminescence and superradiance characteristics of 0.5–1.2-μm thick AlxGa1−xN films grown by molecular-beam epitaxy on sapphire substrates were studied under excitation of the films with low-energy (&amp;lt;20 keV) and high-energy (170 keV) electron beams. In both cases, the luminescence spectra looked quite similarly; they exhibited a band-edge luminescence with x-dependent wavelength ranging from 365 nm to 310 nm and a broadband emission taking over the whole visible spectral region. Superradiance within the broad band was obtained by pumping the samples with powerful an electron beam in the form of an open-discharge-generated filament.